Method and apparatus for performing measurement in wireless communication system

ABSTRACT

The present disclosure relates to performing measurement in wireless communications. According to an embodiment of the present disclosure, a method performed by a wireless device in a wireless communication system comprises: receiving, from a network, information for at least one of a first cell quality threshold or a second cell quality threshold, and information for at least one of a first triggering threshold or a second triggering threshold; identifying a representative cell of each of a plurality of frequencies for measurement; obtaining a representative cell quality for each of the plurality of frequencies based on a measurement on the representative cell of each of the plurality of frequencies; and performing a relaxed measurement on the plurality of frequencies based on a determination that a triggering condition for the relaxed measurement is satisfied, wherein the triggering condition comprises at least one of: a condition that a number of frequencies for which representative cell quality is higher than the first cell quality threshold among the plurality of frequencies is lower than the first triggering threshold; or a condition that a number of frequencies for which representative cell quality is lower than the second cell quality threshold among the plurality of frequencies is higher than the second triggering threshold.

TECHNICAL FIELD

The present disclosure relates to performing measurement in wirelesscommunications.

BACKGROUND

3rd generation partnership project (3GPP) long-term evolution (LTE) is atechnology for enabling high-speed packet communications. Many schemeshave been proposed for the LTE objective including those that aim toreduce user and provider costs, improve service quality, and expand andimprove coverage and system capacity. The 3GPP LTE requires reduced costper bit, increased service availability, flexible use of a frequencyband, a simple structure, an open interface, and adequate powerconsumption of a terminal as an upper-level requirement.

Work has started in international telecommunication union (ITU) and 3GPPto develop requirements and specifications for new radio (NR) systems.3GPP has to identify and develop the technology components needed forsuccessfully standardizing the new RAT timely satisfying both the urgentmarket needs, and the more long-term requirements set forth by the ITUradio communication sector (ITU-R) international mobiletelecommunications (IMT)-2020 process. Further, the NR should be able touse any spectrum band ranging at least up to 100 GHz that may be madeavailable for wireless communications even in a more distant future.

The NR targets a single technical framework addressing all usagescenarios, requirements and deployment scenarios including enhancedmobile broadband (eMBB), massive machine-type-communications (mMTC),ultra-reliable and low latency communications (URLLC), etc. The NR shallbe inherently forward compatible.

In wireless communications, UE may perform neighbor cell measurement forvarious reasons. However, due to a limited power supported by the UE,power consumption for the neighbor cell measurement may be an issue.Therefore, it may be required to reduce the power consumption while theUE is performing neighbour cell measurement.

SUMMARY 1. Technical Problem

An aspect of the present disclosure is to provide method and apparatusfor performing a measurement in a wireless communication system.

Another aspect of the present disclosure is to provide method andapparatus for performing a relaxed measurement in a wirelesscommunication system.

Another aspect of the present disclosure is to provide method andapparatus for evaluating a triggering condition for a relaxedmeasurement in a wireless communication system.

2. Technical Solution

According to an embodiment of the present disclosure, a method performedby a wireless device in a wireless communication system comprises:receiving, from a network, information for at least one of a first cellquality threshold or a second cell quality threshold, and informationfor at least one of a first triggering threshold or a second triggeringthreshold; identifying a representative cell of each of a plurality offrequencies for measurement; obtaining a representative cell quality foreach of the plurality of frequencies based on a measurement on therepresentative cell of each of the plurality of frequencies; andperforming a relaxed measurement on the plurality of frequencies basedon a determination that a triggering condition for the relaxedmeasurement is satisfied, wherein the triggering condition comprises atleast one of: a condition that a number of frequencies for whichrepresentative cell quality is higher than the first cell qualitythreshold among the plurality of frequencies is lower than the firsttriggering threshold; or a condition that a number of frequencies forwhich representative cell quality is lower than the second cell qualitythreshold among the plurality of frequencies is higher than the secondtriggering threshold.

According to an embodiment of the present disclosure, a wireless devicein a wireless communication system comprises: a transceiver; a memory;and at least one processor operatively coupled to the transceiver andthe memory, and configured to: control the transceiver to receive, froma network, information for at least one of a first cell qualitythreshold or a second cell quality threshold, and information for atleast one of a first triggering threshold or a second triggeringthreshold; identify a representative cell of each of a plurality offrequencies for measurement; obtain a representative cell quality foreach of the plurality of frequencies based on a measurement on therepresentative cell of each of the plurality of frequencies; and performa relaxed measurement on the plurality of frequencies based on adetermination that a triggering condition for the relaxed measurement issatisfied, wherein the triggering condition comprises at least one of: acondition that a number of frequencies for which representative cellquality is higher than the first cell quality threshold among theplurality of frequencies is lower than the first triggering threshold;or a condition that a number of frequencies for which representativecell quality is lower than the second cell quality threshold among theplurality of frequencies is higher than the second triggering threshold.

According to an embodiment of the present disclosure, a processor for awireless device in a wireless communication system is configured tocontrol the wireless device to perform operations comprising: receiving,from a network, information for at least one of a first cell qualitythreshold or a second cell quality threshold, and information for atleast one of a first triggering threshold or a second triggeringthreshold; identifying a representative cell of each of a plurality offrequencies for measurement; obtaining a representative cell quality foreach of the plurality of frequencies based on a measurement on therepresentative cell of each of the plurality of frequencies; andperforming a relaxed measurement on the plurality of frequencies basedon a determination that a triggering condition for the relaxedmeasurement is satisfied, wherein the triggering condition comprises atleast one of: a condition that a number of frequencies for whichrepresentative cell quality is higher than the first cell qualitythreshold among the plurality of frequencies is lower than the firsttriggering threshold; or a condition that a number of frequencies forwhich representative cell quality is lower than the second cell qualitythreshold among the plurality of frequencies is higher than the secondtriggering threshold.

According to an embodiment of the present disclosure, acomputer-readable medium having recorded thereon a program forperforming each step of a method on a computer is provided. The methodcomprises: receiving, from a network, information for at least one of afirst cell quality threshold or a second cell quality threshold, andinformation for at least one of a first triggering threshold or a secondtriggering threshold; identifying a representative cell of each of aplurality of frequencies for measurement; obtaining a representativecell quality for each of the plurality of frequencies based on ameasurement on the representative cell of each of the plurality offrequencies; and performing a relaxed measurement on the plurality offrequencies based on a determination that a triggering condition for therelaxed measurement is satisfied, wherein the triggering conditioncomprises at least one of: a condition that a number of frequencies forwhich representative cell quality is higher than the first cell qualitythreshold among the plurality of frequencies is lower than the firsttriggering threshold; or a condition that a number of frequencies forwhich representative cell quality is lower than the second cell qualitythreshold among the plurality of frequencies is higher than the secondtriggering threshold.

According to an embodiment of the present disclosure, a method performedby a base station (BS) in a wireless communication system comprises:transmitting, to a wireless device, information for at least one of afirst cell quality threshold or a second cell quality threshold, andinformation for at least one of a first triggering threshold or a secondtriggering threshold, wherein the wireless device is configured to:identify a representative cell of each of a plurality of frequencies formeasurement; obtain a representative cell quality for each of theplurality of frequencies based on a measurement on the representativecell of each of the plurality of frequencies; and perform a relaxedmeasurement on the plurality of frequencies based on a determinationthat a triggering condition for the relaxed measurement is satisfied,wherein the triggering condition comprises at least one of: a conditionthat a number of frequencies for which representative cell quality ishigher than the first cell quality threshold among the plurality offrequencies is lower than the first triggering threshold; or a conditionthat a number of frequencies for which representative cell quality islower than the second cell quality threshold among the plurality offrequencies is higher than the second triggering threshold.

According to an embodiment of the present disclosure, a base station(BS) in a wireless communication system comprises: a transceiver; amemory; and at least one processor operatively coupled to thetransceiver and the memory, and configured to: control the transceiverto transmit, to a wireless device, information for at least one of afirst cell quality threshold or a second cell quality threshold, andinformation for at least one of a first triggering threshold or a secondtriggering threshold, wherein the wireless device is configured to:identify a representative cell of each of a plurality of frequencies formeasurement; obtain a representative cell quality for each of theplurality of frequencies based on a measurement on the representativecell of each of the plurality of frequencies; and perform a relaxedmeasurement on the plurality of frequencies based on a determinationthat a triggering condition for the relaxed measurement is satisfied,wherein the triggering condition comprises at least one of: a conditionthat a number of frequencies for which representative cell quality ishigher than the first cell quality threshold among the plurality offrequencies is lower than the first triggering threshold; or a conditionthat a number of frequencies for which representative cell quality islower than the second cell quality threshold among the plurality offrequencies is higher than the second triggering threshold.

3. Advantageous Effect

The present disclosure can have various advantageous effects.

For example, the UE may determine whether to perform a relaxedmeasurement by considering not only a serving cell quality but also aneighbor cell quality so that the UE can perform a mobility when theneighbor cell quality is good enough.

For example, by considering not only a serving cell quality but also aneighbor cell quality, the UE can perform a relaxed measurement when theneighbor cell quality is bad enough.

Advantageous effects which can be obtained through specific embodimentsof the present disclosure are not limited to the advantageous effectslisted above. For example, there may be a variety of technical effectsthat a person having ordinary skill in the related art can understandand/or derive from the present disclosure. Accordingly, the specificeffects of the present disclosure are not limited to those explicitlydescribed herein, but may include various effects that may be understoodor derived from the technical features of the present disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows examples of 5G usage scenarios to which the technicalfeatures of the present disclosure can be applied.

FIG. 2 shows an example of a wireless communication system to which thetechnical features of the present disclosure can be applied.

FIG. 3 shows an example of a wireless communication system to which thetechnical features of the present disclosure can be applied.

FIG. 4 shows another example of a wireless communication system to whichthe technical features of the present disclosure can be applied.

FIG. 5 shows a block diagram of a user plane protocol stack to which thetechnical features of the present disclosure can be applied.

FIG. 6 shows a block diagram of a control plane protocol stack to whichthe technical features of the present disclosure can be applied.

FIG. 7 illustrates a frame structure in a 3GPP based wirelesscommunication system.

FIG. 8 illustrates a data flow example in the 3GPP NR system.

FIG. 9 shows an example of possible RRC states in a wirelesscommunication system to which technical features of the presentdisclosure can be applied.

FIG. 10 shows an example of a method for a relaxed measurement accordingto an embodiment of the present disclosure.

FIG. 11 shows an example of a signal flow for a relaxed measurementaccording to an embodiment of the present disclosure.

FIG. 12 shows an example of a method for measurement relaxation based onthe number of frequencies with cell quality according to an embodimentof the present disclosure.

FIG. 13 shows a UE to implement an embodiment of the present disclosure.

FIG. 14 shows another example of a wireless communication system towhich the technical features of the present disclosure can be applied.

FIG. 15 shows an example of an AI device to which the technical featuresof the present disclosure can be applied.

FIG. 16 shows an example of an AI system to which the technical featuresof the present disclosure can be applied.

DETAILED DESCRIPTION

The technical features described below may be used by a communicationstandard by the 3rd generation partnership project (3GPP)standardization organization, a communication standard by the instituteof electrical and electronics engineers (IEEE), etc. For example, thecommunication standards by the 3GPP standardization organization includelong-term evolution (LTE) and/or evolution of LTE systems. The evolutionof LTE systems includes LTE-advanced (LTE-A), LTE-A Pro, and/or 5G newradio (NR). The communication standard by the IEEE standardizationorganization includes a wireless local area network (WLAN) system suchas IEEE 802.11a/b/g/n/ac/ax. The above system uses various multipleaccess technologies such as orthogonal frequency division multipleaccess (OFDMA) and/or single carrier frequency division multiple access(SC-FDMA) for downlink (DL) and/or uplink (UL). For example, only OFDMAmay be used for DL and only SC-FDMA may be used for UL. Alternatively,OFDMA and SC-FDMA may be used for DL and/or UL.

Here, the radio communication technologies implemented in the wirelessdevices in the present disclosure may include narrowbandinternet-of-things (NB-IoT) technology for low-power communication aswell as LTE, NR and 6G. For example, NB-IoT technology may be an exampleof low power wide area network (LPWAN) technology, may be implemented inspecifications such as LTE Cat NB1 and/or LTE Cat NB2, and may not belimited to the above-mentioned names. Additionally and/or alternatively,the radio communication technologies implemented in the wireless devicesin the present disclosure may communicate based on LTE-M technology. Forexample, LTE-M technology may be an example of LPWAN technology and becalled by various names such as enhanced machine type communication(eMTC). For example, LTE-M technology may be implemented in at least oneof the various specifications, such as 1) LTE Cat 0, 2) LTE Cat M1, 3)LTE Cat M2, 4) LTE non-bandwidth limited (non-BL), 5) LTE-MTC, 6) LTEMachine Type Communication, and/or 7) LTE M, and may not be limited tothe above-mentioned names Additionally and/or alternatively, the radiocommunication technologies implemented in the wireless devices in thepresent disclosure may include at least one of ZigBee, Bluetooth, and/orLPWAN which take into account low-power communication, and may not belimited to the above-mentioned names. For example, ZigBee technology maygenerate personal area networks (PANs) associated with small/low-powerdigital communication based on various specifications such as IEEE802.15.4 and may be called various names.

In the present disclosure, “A or B” may mean “only A”, “only B”, or“both A and B”. In other words, “A or B” in the present disclosure maybe interpreted as “A and/or B”. For example, “A, B or C” in the presentdisclosure may mean “only A”, “only B”, “only C”, or “any combination ofA, B and C”.

In the present disclosure, slash (/) or comma (,) may mean “and/or”. Forexample, “A/B” may mean “A and/or B”. Accordingly, “A/B” may mean “onlyA”, “only B”, or “both A and B”. For example, “A, B, C” may mean “A, Bor C”.

In the present disclosure, “at least one of A and B” may mean “only A”,“only B” or “both A and B”. In addition, the expression “at least one ofA or B” or “at least one of A and/or B” in the present disclosure may beinterpreted as same as “at least one of A and B”.

In addition, in the present disclosure, “at least one of A, B and C” maymean “only A”, “only B”, “only C”, or “any combination of A, B and C”.In addition, “at least one of A, B or C” or “at least one of A, B and/orC” may mean “at least one of A, B and C”.

Also, parentheses used in the present disclosure may mean “for example”.In detail, when it is shown as “control information (PDCCH)”, “PDCCH”may be proposed as an example of “control information”. In other words,“control information” in the present disclosure is not limited to“PDCCH”, and “PDDCH” may be proposed as an example of “controlinformation”. In addition, even when shown as “control information(i.e., PDCCH)”, “PDCCH” may be proposed as an example of “controlinformation”.

Technical features that are separately described in one drawing in thepresent disclosure may be implemented separately or simultaneously.

The terms used throughout the disclosure can be defined as thefollowings:

“Suitable cell” is a cell on which a UE may camp.

Throughout the disclosure, the terms ‘radio access network (RAN) node’,‘base station’, ‘eNB’, ‘gNB’ and ‘cell’ may be used interchangeably.Further, a UE may be a kind of a wireless device, and throughout thedisclosure, the terms ‘UE’ and ‘wireless device’ may be usedinterchangeably.

Throughout the disclosure, the terms ‘cell quality’, ‘signal strength’,‘signal quality’, ‘channel state’, ‘channel quality’, ‘channelstate/reference signal received power (RSRP)’ and ‘reference signalreceived quality (RSRQ)’ may be used interchangeably.

The following drawings are created to explain specific embodiments ofthe present disclosure. The names of the specific devices or the namesof the specific signals/messages/fields shown in the drawings areprovided by way of example, and thus the technical features of thepresent disclosure are not limited to the specific names used in thefollowing drawings.

FIG. 1 shows examples of 5G usage scenarios to which the technicalfeatures of the present disclosure can be applied.

The 5G usage scenarios shown in FIG. 1 are only exemplary, and thetechnical features of the present disclosure can be applied to other 5Gusage scenarios which are not shown in FIG. 1 .

Referring to FIG. 1 , the three main requirements areas of 5G include(1) enhanced mobile broadband (eMBB) domain, (2) massive machine typecommunication (mMTC) area, and (3) ultra-reliable and low latencycommunications (URLLC) area. Some use cases may require multiple areasfor optimization and, other use cases may only focus on only one keyperformance indicator (KPI). 5G is to support these various use cases ina flexible and reliable way.

eMBB focuses on across-the-board enhancements to the data rate, latency,user density, capacity and coverage of mobile broadband access. The eMBBaims ˜10 Gbps of throughput. eMBB far surpasses basic mobile Internetaccess and covers rich interactive work and media and entertainmentapplications in cloud and/or augmented reality. Data is one of the keydrivers of 5G and may not be able to see dedicated voice services forthe first time in the 5G era. In 5G, the voice is expected to beprocessed as an application simply using the data connection provided bythe communication system. The main reason for the increased volume oftraffic is an increase in the size of the content and an increase in thenumber of applications requiring high data rates. Streaming services(audio and video), interactive video and mobile Internet connectivitywill become more common as more devices connect to the Internet. Many ofthese applications require always-on connectivity to push real-timeinformation and notifications to the user. Cloud storage andapplications are growing rapidly in mobile communication platforms,which can be applied to both work and entertainment. Cloud storage is aspecial use case that drives growth of uplink data rate. 5G is also usedfor remote tasks on the cloud and requires much lower end-to-end delayto maintain a good user experience when the tactile interface is used.In entertainment, for example, cloud games and video streaming areanother key factor that increases the demand for mobile broadbandcapabilities. Entertainment is essential in smartphones and tabletsanywhere, including high mobility environments such as trains, cars andairplanes. Another use case is augmented reality and informationretrieval for entertainment. Here, augmented reality requires very lowlatency and instantaneous data amount.

mMTC is designed to enable communication between devices that arelow-cost, massive in number and battery-driven, intended to supportapplications such as smart metering, logistics, and field and bodysensors. mMTC aims ˜10 years on battery and/or ˜1 million devices/km2.mMTC allows seamless integration of embedded sensors in all areas and isone of the most widely used 5G applications. Potentially by 2020,internet-of-things (IoT) devices are expected to reach 20.4 billion.Industrial IoT is one of the areas where 5G plays a key role in enablingsmart cities, asset tracking, smart utilities, agriculture and securityinfrastructures.

URLLC will make it possible for devices and machines to communicate withultra-reliability, very low latency and high availability, making itideal for vehicular communication, industrial control, factoryautomation, remote surgery, smart grids and public safety applications.URLLC aims ˜1 ms of latency. URLLC includes new services that willchange the industry through links with ultra-reliability/low latency,such as remote control of key infrastructure and self-driving vehicles.The level of reliability and latency is essential for smart gridcontrol, industrial automation, robotics, drones control andcoordination.

Next, a plurality of use cases included in the triangle of FIG. 1 willbe described in more detail.

5G can complement fiber-to-the-home (FTTH) and cable-based broadband (orDOCSIS) as a means of delivering streams rated from hundreds of megabitsper second to gigabits per second. This high speed can be required todeliver TVs with resolutions of 4K or more (6K, 8K and above) as well asvirtual reality (VR) and augmented reality (AR). VR and AR applicationsinclude mostly immersive sporting events. Certain applications mayrequire special network settings. For example, in the case of a VR game,a game company may need to integrate a core server with an edge networkserver of a network operator to minimize delay.

Automotive is expected to become an important new driver for 5G, withmany use cases for mobile communications to vehicles. For example,entertainment for passengers demands high capacity and high mobilebroadband at the same time. This is because future users will continueto expect high-quality connections regardless of their location andspeed. Another use case in the automotive sector is an augmented realitydashboard. The driver can identify an object in the dark on top of whatis being viewed through the front window through the augmented realitydashboard. The augmented reality dashboard displays information thatwill inform the driver about the object's distance and movement. In thefuture, the wireless module enables communication between vehicles,information exchange between the vehicle and the supportinginfrastructure, and information exchange between the vehicle and otherconnected devices (e.g. devices accompanied by a pedestrian). The safetysystem allows the driver to guide the alternative course of action sothat he can drive more safely, thereby reducing the risk of accidents.The next step will be a remotely controlled vehicle or self-drivingvehicle. This requires a very reliable and very fast communicationbetween different self-driving vehicles and between vehicles andinfrastructure. In the future, a self-driving vehicle will perform alldriving activities, and the driver will focus only on traffic that thevehicle itself cannot identify. The technical requirements ofself-driving vehicles require ultra-low latency and high-speedreliability to increase traffic safety to a level not achievable byhumans.

Smart cities and smart homes, which are referred to as smart societies,will be embedded in high density wireless sensor networks. Thedistributed network of intelligent sensors will identify conditions forcost and energy-efficient maintenance of a city or house. A similarsetting can be performed for each home. Temperature sensors, windows andheating controllers, burglar alarms and appliances are all wirelesslyconnected. Many of these sensors typically require low data rate, lowpower and low cost. However, for example, real-time high-definition (HD)video may be required for certain types of devices for monitoring.

The consumption and distribution of energy, including heat or gas, ishighly dispersed, requiring automated control of distributed sensornetworks. The smart grid interconnects these sensors using digitalinformation and communication technologies to collect and act oninformation. This information can include supplier and consumerbehavior, allowing the smart grid to improve the distribution of fuel,such as electricity, in terms of efficiency, reliability, economy,production sustainability, and automated methods. The smart grid can beviewed as another sensor network with low latency.

The health sector has many applications that can benefit from mobilecommunications. Communication systems can support telemedicine toprovide clinical care in remote locations. This can help to reducebarriers to distance and improve access to health services that are notcontinuously available in distant rural areas. It is also used to savelives in critical care and emergency situations. Mobile communicationbased wireless sensor networks can provide remote monitoring and sensorsfor parameters such as heart rate and blood pressure.

Wireless and mobile communications are becoming increasingly importantin industrial applications. Wiring costs are high for installation andmaintenance. Thus, the possibility of replacing a cable with a wirelesslink that can be reconfigured is an attractive opportunity in manyindustries. However, achieving this requires that wireless connectionsoperate with similar delay, reliability, and capacity as cables and thattheir management is simplified. Low latency and very low errorprobabilities are new requirements that need to be connected to 5G.

Logistics and freight tracking are important use cases of mobilecommunications that enable tracking of inventory and packages anywhereusing location based information systems. Use cases of logistics andfreight tracking typically require low data rates, but require a largerange and reliable location information.

NR supports multiple numerology (or, subcarrier spacing (SCS)) tosupport various 5G services. For example, when the SCS is 15 kHz, widearea in traditional cellular bands may be supported. When the SCS is 30kHz/60 kHz, dense-urban, lower latency and wider carrier bandwidth maybe supported. When the SCS is 60 kHz or higher, a bandwidth greater than24.25 GHz may be supported to overcome phase noise.

The NR frequency band may be defined as two types of frequency range,i.e., FR1 and FR2. The numerical value of the frequency range may bechanged. For example, the frequency ranges of the two types (FR1 andFR2) may be as shown in Table 1 below. For ease of explanation, in thefrequency ranges used in the NR system, FR1 may mean “sub 6 GHz range”,FR2 may mean “above 6 GHz range,” and may be referred to as millimeterwave (mmW).

TABLE 1 Frequency Range Corresponding Subcarrier designation frequencyrange Spacing FR1 450 MHz-6000 MHz 15, 30, 60 kHz FR2 24250 MHz-52600MHz  60, 120, 240 kHz

As mentioned above, the numerical value of the frequency range of the NRsystem may be changed. For example, FR1 may include a frequency band of410 MHz to 7125 MHz as shown in Table 2 below. That is, FR1 may includea frequency band of 6 GHz (or 5850, 5900, 5925 MHz, etc.) or more. Forexample, a frequency band of 6 GHz (or 5850, 5900, 5925 MHz, etc.) ormore included in FR1 may include an unlicensed band. Unlicensed bandsmay be used for a variety of purposes, for example for communication forvehicles (e.g., autonomous driving).

TABLE 2 Frequency Range Corresponding Subcarrier designation frequencyrange Spacing FR1 410 MHz-7125 MHz 15, 30, 60 kHz FR2 24250 MHz-52600MHz  60, 120, 240 kHz

FIG. 2 shows an example of a wireless communication system to which thetechnical features of the present disclosure can be applied. Referringto FIG. 2 , the wireless communication system may include a first device210 and a second device 220.

The first device 210 includes a base station, a network node, atransmitting UE, a receiving UE, a wireless device, a wirelesscommunication device, a vehicle, a vehicle equipped with an autonomousdriving function, a connected car, a drone, an unmanned aerial vehicle(UAV), an artificial intelligence (AI) module, a robot, an AR device, aVR device, a mixed reality (MR) device, a hologram device, a publicsafety device, an MTC device, an IoT device, a medical device, afin-tech device (or, a financial device), a security device, aclimate/environmental device, a device related to 5G services, or adevice related to the fourth industrial revolution.

The second device 220 includes a base station, a network node, atransmitting UE, a receiving UE, a wireless device, a wirelesscommunication device, a vehicle, a vehicle equipped with an autonomousdriving function, a connected car, a drone, a UAV, an AI module, arobot, an AR device, a VR device, an MR device, a hologram device, apublic safety device, an MTC device, an IoT device, a medical device, afin-tech device (or, a financial device), a security device, aclimate/environmental device, a device related to 5G services, or adevice related to the fourth industrial revolution.

For example, the UE may include a mobile phone, a smart phone, a laptopcomputer, a digital broadcasting terminal, a personal digital assistant(PDA), a portable multimedia player (PMP), a navigation device, a slatepersonal computer (PC), a tablet PC, an ultrabook, a wearable device(e.g. a smartwatch, a smart glass, a head mounted display (HMD)) . Forexample, the HMD may be a display device worn on the head. For example,the HMD may be used to implement AR, VR and/or MR.

For example, the drone may be a flying object that is flying by a radiocontrol signal without a person boarding it. For example, the VR devicemay include a device that implements an object or background in thevirtual world. For example, the AR device may include a device thatimplements connection of an object and/or a background of a virtualworld to an object and/or a background of the real world. For example,the MR device may include a device that implements fusion of an objectand/or a background of a virtual world to an object and/or a backgroundof the real world. For example, the hologram device may include a devicethat implements a 360-degree stereoscopic image by recording and playingstereoscopic information by utilizing a phenomenon of interference oflight generated by the two laser lights meeting with each other, calledholography. For example, the public safety device may include a videorelay device or a video device that can be worn by the user's body. Forexample, the MTC device and the IoT device may be a device that do notrequire direct human intervention or manipulation. For example, the MTCdevice and the IoT device may include a smart meter, a vending machine,a thermometer, a smart bulb, a door lock and/or various sensors. Forexample, the medical device may be a device used for the purpose ofdiagnosing, treating, alleviating, handling, or preventing a disease.For example, the medical device may be a device used for the purpose ofdiagnosing, treating, alleviating, or correcting an injury or disorder.For example, the medical device may be a device used for the purpose ofinspecting, replacing or modifying a structure or function. For example,the medical device may be a device used for the purpose of controllingpregnancy. For example, the medical device may include a treatmentdevice, a surgical device, an (in vitro) diagnostic device, a hearingaid and/or a procedural device, etc. For example, a security device maybe a device installed to prevent the risk that may occur and to maintainsafety. For example, the security device may include a camera, aclosed-circuit TV (CCTV), a recorder, or a black box. For example, thefin-tech device may be a device capable of providing financial servicessuch as mobile payment. For example, the fin-tech device may include apayment device or a point of sales (POS). For example, theclimate/environmental device may include a device for monitoring orpredicting the climate/environment.

The first device 210 may include at least one or more processors, suchas a processor 211, at least one memory, such as a memory 212, and atleast one transceiver, such as a transceiver 213. The processor 211 mayperform the functions, procedures, and/or methods of the first devicedescribed throughout the disclosure. The processor 211 may perform oneor more protocols. For example, the processor 211 may perform one ormore layers of the air interface protocol. The memory 212 is connectedto the processor 211 and may store various types of information and/orinstructions. The transceiver 213 is connected to the processor 211 andmay be controlled by the processor 211 to transmit and receive wirelesssignals.

The second device 220 may include at least one or more processors, suchas a processor 221, at least one memory, such as a memory 222, and atleast one transceiver, such as a transceiver 223. The processor 221 mayperform the functions, procedures, and/or methods of the second device220 described throughout the disclosure. The processor 221 may performone or more protocols. For example, the processor 221 may perform one ormore layers of the air interface protocol. The memory 222 is connectedto the processor 221 and may store various types of information and/orinstructions. The transceiver 223 is connected to the processor 221 andmay be controlled by the processor 221 to transmit and receive wirelesssignals.

The memory 212, 222 may be connected internally or externally to theprocessor 211, 212, or may be connected to other processors via avariety of technologies such as wired or wireless connections.

The first device 210 and/or the second device 220 may have more than oneantenna. For example, antenna 214 and/or antenna 224 may be configuredto transmit and receive wireless signals.

FIG. 3 shows an example of a wireless communication system to which thetechnical features of the present disclosure can be applied.

Specifically, FIG. 3 shows a system architecture based on anevolved-UMTS terrestrial radio access network (E-UTRAN). Theaforementioned LTE is a part of an evolved-UTMS (e-UMTS) using theE-UTRAN.

Referring to FIG. 3 , the wireless communication system includes one ormore user equipment (UE) 310, an E-UTRAN and an evolved packet core(EPC). The UE 310 refers to a communication equipment carried by a user.The UE 310 may be fixed or mobile. The UE 310 may be referred to asanother terminology, such as a mobile station (MS), a user terminal(UT), a subscriber station (SS), a wireless device, etc.

The E-UTRAN consists of one or more evolved NodeB (eNB) 320. The eNB 320provides the E-UTRA user plane and control plane protocol terminationstowards the UE 10. The eNB 320 is generally a fixed station thatcommunicates with the UE 310. The eNB 320 hosts the functions, such asinter-cell radio resource management (RRM), radio bearer (RB) control,connection mobility control, radio admission control, measurementconfiguration/provision, dynamic resource allocation (scheduler), etc.The eNB 320 may be referred to as another terminology, such as a basestation (BS), a base transceiver system (BTS), an access point (AP),etc.

A downlink (DL) denotes communication from the eNB 320 to the UE 310. Anuplink (UL) denotes communication from the UE 310 to the eNB 320. Asidelink (SL) denotes communication between the UEs 310. In the DL, atransmitter may be a part of the eNB 320, and a receiver may be a partof the UE 310. In the UL, the transmitter may be a part of the UE 310,and the receiver may be a part of the eNB 320. In the SL, thetransmitter and receiver may be a part of the UE 310.

The EPC includes a mobility management entity (MME), a serving gateway(S-GW) and a packet data network (PDN) gateway (P-GW). The MME hosts thefunctions, such as non-access stratum (NAS) security, idle statemobility handling, evolved packet system (EPS) bearer control, etc. TheS-GW hosts the functions, such as mobility anchoring, etc. The S-GW is agateway having an E-UTRAN as an endpoint. For convenience, MME/S-GW 330will be referred to herein simply as a “gateway,” but it is understoodthat this entity includes both the MME and S-GW. The P-GW hosts thefunctions, such as UE Internet protocol (IP) address allocation, packetfiltering, etc. The P-GW is a gateway having a PDN as an endpoint. TheP-GW is connected to an external network.

The UE 310 is connected to the eNB 320 by means of the Uu interface. TheUEs 310 are interconnected with each other by means of the PC5interface. The eNBs 320 are interconnected with each other by means ofthe X2 interface. The eNBs 320 are also connected by means of the S1interface to the EPC, more specifically to the MME by means of theS1-MME interface and to the S-GW by means of the S1-U interface. The S1interface supports a many-to-many relation between MMEs/S-GWs and eNBs.

FIG. 4 shows another example of a wireless communication system to whichthe technical features of the present disclosure can be applied.

Specifically, FIG. 4 shows a system architecture based on a 5G NR. Theentity used in the 5G NR (hereinafter, simply referred to as “NR”) mayabsorb some or all of the functions of the entities introduced in FIG. 3(e.g. eNB, MME, S-GW). The entity used in the NR may be identified bythe name “NG” for distinction from the LTE/LTE-A.

Referring to FIG. 4 , the wireless communication system includes one ormore UE 410, a next-generation RAN (NG-RAN) and a 5th generation corenetwork (5GC). The NG-RAN consists of at least one NG-RAN node. TheNG-RAN node is an entity corresponding to the eNB 320 shown in FIG. 3 .The NG-RAN node consists of at least one gNB 421 and/or at least oneng-eNB 422. The gNB 421 provides NR user plane and control planeprotocol terminations towards the UE 410. The ng-eNB 422 provides E-UTRAuser plane and control plane protocol terminations towards the UE 410.

The 5GC includes an access and mobility management function (AMF), auser plane function (UPF) and a session management function (SMF). TheAMF hosts the functions, such as NAS security, idle state mobilityhandling, etc. The AMF is an entity including the functions of theconventional MME. The UPF hosts the functions, such as mobilityanchoring, protocol data unit (PDU) handling. The UPF an entityincluding the functions of the conventional S-GW. The SMF hosts thefunctions, such as UE IP address allocation, PDU session control.

The gNBs 421 and ng-eNBs 422 are interconnected with each other by meansof the Xn interface. The gNBs 421 and ng-eNBs 422 are also connected bymeans of the NG interfaces to the 5GC, more specifically to the AMF bymeans of the NG-C interface and to the UPF by means of the NG-Uinterface.

A protocol structure between network entities described above isdescribed. On the system of FIG. 3 and/or FIG. 4 , layers of a radiointerface protocol between the UE and the network (e.g. NG-RAN and/orE-UTRAN) may be classified into a first layer (L1), a second layer (L2),and a third layer (L3) based on the lower three layers of the opensystem interconnection (OSI) model that is well-known in thecommunication system.

FIG. 5 shows a block diagram of a user plane protocol stack to which thetechnical features of the present disclosure can be applied. FIG. 6shows a block diagram of a control plane protocol stack to which thetechnical features of the present disclosure can be applied.

The user/control plane protocol stacks shown in FIG. 5 and FIG. 6 areused in NR. However, user/control plane protocol stacks shown in FIG. 5and FIG. 6 may be used in LTE/LTE-A without loss of generality, byreplacing gNB/AMF with eNB/MME.

Referring to FIG. 5 and FIG. 6 , a physical (PHY) layer belonging to L1.The PHY layer offers information transfer services to media accesscontrol (MAC) sublayer and higher layers. The PHY layer offers to theMAC sublayer transport channels. Data between the MAC sublayer and thePHY layer is transferred via the transport channels. Between differentPHY layers, i.e., between a PHY layer of a transmission side and a PHYlayer of a reception side, data is transferred via the physicalchannels.

The MAC sublayer belongs to L2. The main services and functions of theMAC sublayer include mapping between logical channels and transportchannels, multiplexing/de-multiplexing of MAC service data units (SDUs)belonging to one or different logical channels into/from transportblocks (TB) delivered to/from the physical layer on transport channels,scheduling information reporting, error correction through hybridautomatic repeat request (HARQ), priority handling between UEs by meansof dynamic scheduling, priority handling between logical channels of oneUE by means of logical channel prioritization (LCP), etc. The MACsublayer offers to the radio link control (RLC) sublayer logicalchannels.

The RLC sublayer belong to L2. The RLC sublayer supports threetransmission modes, i.e. transparent mode (TM), unacknowledged mode(UM), and acknowledged mode (AM), in order to guarantee various qualityof services (QoS) required by radio bearers. The main services andfunctions of the RLC sublayer depend on the transmission mode. Forexample, the RLC sublayer provides transfer of upper layer PDUs for allthree modes, but provides error correction through ARQ for AM only. InLTE/LTE-A, the RLC sublayer provides concatenation, segmentation andreassembly of RLC SDUs (only for UM and AM data transfer) andre-segmentation of RLC data PDUs (only for AM data transfer). In NR, theRLC sublayer provides segmentation (only for AM and UM) andre-segmentation (only for AM) of RLC SDUs and reassembly of SDU (onlyfor AM and UM). That is, the NR does not support concatenation of RLCSDUs. The RLC sublayer offers to the packet data convergence protocol(PDCP) sublayer RLC channels.

The PDCP sublayer belong to L2. The main services and functions of thePDCP sublayer for the user plane include header compression anddecompression, transfer of user data, duplicate detection, PDCP PDUrouting, retransmission of PDCP SDUs, ciphering and deciphering, etc.The main services and functions of the PDCP sublayer for the controlplane include ciphering and integrity protection, transfer of controlplane data, etc.

The service data adaptation protocol (SDAP) sublayer belong to L2. TheSDAP sublayer is only defined in the user plane. The SDAP sublayer isonly defined for NR. The main services and functions of SDAP include,mapping between a QoS flow and a data radio bearer (DRB), and markingQoS flow ID (QFI) in both DL and UL packets. The SDAP sublayer offers to5GC QoS flows.

A radio resource control (RRC) layer belongs to L3. The RRC layer isonly defined in the control plane. The RRC layer controls radioresources between the UE and the network. To this end, the RRC layerexchanges RRC messages between the UE and the BS. The main services andfunctions of the RRC layer include broadcast of system informationrelated to AS and NAS, paging, establishment, maintenance and release ofan RRC connection between the UE and the network, security functionsincluding key management, establishment, configuration, maintenance andrelease of radio bearers, mobility functions, QoS management functions,UE measurement reporting and control of the reporting, NAS messagetransfer to/from NAS from/to UE.

In other words, the RRC layer controls logical channels, transportchannels, and physical channels in relation to the configuration,reconfiguration, and release of radio bearers. A radio bearer refers toa logical path provided by L1 (PHY layer) and L2 (MAC/RLC/PDCP/SDAPsublayer) for data transmission between a UE and a network. Setting theradio bearer means defining the characteristics of the radio protocollayer and the channel for providing a specific service, and setting eachspecific parameter and operation method. Radio bearer may be dividedinto signaling RB (SRB) and data RB (DRB). The SRB is used as a path fortransmitting RRC messages in the control plane, and the DRB is used as apath for transmitting user data in the user plane.

An RRC state indicates whether an RRC layer of the UE is logicallyconnected to an RRC layer of the E-UTRAN. In LTE/LTE-A, when the RRCconnection is established between the RRC layer of the UE and the RRClayer of the E-UTRAN, the UE is in the RRC connected state(RRC_CONNECTED). Otherwise, the UE is in the RRC idle state (RRC_IDLE).In NR, the RRC inactive state (RRC_INACTIVE) is additionally introduced.RRC_INACTIVE may be used for various purposes. For example, the massivemachine type communications (MMTC) UEs can be efficiently managed inRRC_INACTIVE. When a specific condition is satisfied, transition is madefrom one of the above three states to the other.

A predetermined operation may be performed according to the RRC state.In RRC_IDLE, public land mobile network (PLMN) selection, broadcast ofsystem information (SI), cell re-selection mobility, core network (CN)paging and discontinuous reception (DRX) configured by NAS may beperformed. The UE shall have been allocated an identifier (ID) whichuniquely identifies the UE in a tracking area. No RRC context stored inthe BS.

In RRC_CONNECTED, the UE has an RRC connection with the network (i.e.E-UTRAN/NG-RAN). Network-CN connection (both C/U-planes) is alsoestablished for UE. The UE AS context is stored in the network and theUE. The RAN knows the cell which the UE belongs to. The network cantransmit and/or receive data to/from UE. Network controlled mobilityincluding measurement is also performed.

Most of operations performed in RRC_IDLE may be performed inRRC_INACTIVE. But, instead of CN paging in RRC_IDLE, RAN paging isperformed in RRC_INACTIVE. In other words, in RRC_IDLE, paging formobile terminated (MT) data is initiated by core network and paging areais managed by core network. In RRC_INACTIVE, paging is initiated byNG-RAN, and RAN-based notification area (RNA) is managed by NG-RAN.Further, instead of DRX for CN paging configured by NAS in RRC_IDLE, DRXfor RAN paging is configured by NG-RAN in RRC_INACTIVE. Meanwhile, inRRC_INACTIVE, 5GC-NG-RAN connection (both C/U-planes) is established forUE, and the UE AS context is stored in NG-RAN and the UE. NG-RAN knowsthe RNA which the UE belongs to.

NAS layer is located at the top of the RRC layer. The NAS controlprotocol performs the functions, such as authentication, mobilitymanagement, security control.

The physical channels may be modulated according to OFDM processing andutilizes time and frequency as radio resources. The physical channelsconsist of a plurality of orthogonal frequency division multiplexing(01-DM) symbols in time domain and a plurality of subcarriers infrequency domain. One subframe consists of a plurality of OFDM symbolsin the time domain. A resource block is a resource allocation unit, andconsists of a plurality of OFDM symbols and a plurality of subcarriers.In addition, each subframe may use specific subcarriers of specific OFDMsymbols (e.g. first OFDM symbol) of the corresponding subframe for aphysical downlink control channel (PDCCH), i.e. L1/L2 control channel. Atransmission time interval (TTI) is a basic unit of time used by ascheduler for resource allocation. The TTI may be defined in units ofone or a plurality of slots, or may be defined in units of mini-slots.

The transport channels are classified according to how and with whatcharacteristics data are transferred over the radio interface. DLtransport channels include a broadcast channel (BCH) used fortransmitting system information, a downlink shared channel (DL-SCH) usedfor transmitting user traffic or control signals, and a paging channel(PCH) used for paging a UE. UL transport channels include an uplinkshared channel (UL-SCH) for transmitting user traffic or control signalsand a random access channel (RACH) normally used for initial access to acell.

Different kinds of data transfer services are offered by MAC sublayer.Each logical channel type is defined by what type of information istransferred. Logical channels are classified into two groups: controlchannels and traffic channels.

Control channels are used for the transfer of control plane informationonly. The control channels include a broadcast control channel (BCCH), apaging control channel (PCCH), a common control channel (CCCH) and adedicated control channel (DCCH). The BCCH is a DL channel forbroadcasting system control information. The PCCH is DL channel thattransfers paging information, system information change notifications.The CCCH is a channel for transmitting control information between UEsand network. This channel is used for UEs having no RRC connection withthe network. The DCCH is a point-to-point bi-directional channel thattransmits dedicated control information between a UE and the network.This channel is used by UEs having an RRC connection.

Traffic channels are used for the transfer of user plane informationonly. The traffic channels include a dedicated traffic channel (DTCH).The DTCH is a point-to-point channel, dedicated to one UE, for thetransfer of user information. The DTCH can exist in both UL and DL.

Regarding mapping between the logical channels and transport channels,in DL, BCCH can be mapped to BCH, BCCH can be mapped to DL-SCH, PCCH canbe mapped to PCH, CCCH can be mapped to DL-SCH, DCCH can be mapped toDL-SCH, and DTCH can be mapped to DL-SCH. In UL, CCCH can be mapped toUL-SCH, DCCH can be mapped to UL- SCH, and DTCH can be mapped to UL-SCH.

FIG. 7 illustrates a frame structure in a 3GPP based wirelesscommunication system.

The frame structure illustrated in FIG. 7 is purely exemplary and thenumber of subframes, the number of slots, and/or the number of symbolsin a frame may be variously changed. In the 3GPP based wirelesscommunication system, an OFDM numerology (e.g., subcarrier spacing(SCS), transmission time interval (TTI) duration) may be differentlyconfigured between a plurality of cells aggregated for one UE. Forexample, if a UE is configured with different SCSs for cells aggregatedfor the cell, an (absolute time) duration of a time resource (e.g. asubframe, a slot, or a TTI) including the same number of symbols may bedifferent among the aggregated cells. Herein, symbols may include OFDMsymbols (or CP-OFDM symbols), SC-FDMA symbols (or discrete Fouriertransform-spread-OFDM (DFT-s-OFDM) symbols).

Referring to FIG. 7 , downlink and uplink transmissions are organizedinto frames. Each frame has Tf=10 ms duration. Each frame is dividedinto two half-frames, where each of the half-frames has 5 ms duration.Each half-frame consists of 5 subframes, where the duration Tsf persubframe is 1 ms. Each subframe is divided into slots and the number ofslots in a subframe depends on a subcarrier spacing. Each slot includes14 or 12 OFDM symbols based on a cyclic prefix (CP). In a normal CP,each slot includes 14 OFDM symbols and, in an extended CP, each slotincludes 12 OFDM symbols. The numerology is based on exponentiallyscalable subcarrier spacing Δf=2u*15 kHz. The following table shows thenumber of OFDM symbols per slot, the number of slots per frame, and thenumber of slots per for the normal CP, according to the subcarrierspacing Δf=2u*15 kHz.

TABLE 3 u Nslotsymb Nframe,uslot Nsubframe,uslot 0 14 10 1 1 14 20 2 214 40 4 3 14 80 8 4 14 160 16

The following table shows the number of OFDM symbols per slot, thenumber of slots per frame, and the number of slots per for the extendedCP, according to the subcarrier spacing Δf=2u*15 kHz.

TABLE 4 u Nslotsymb Nframe,uslot Nsubframe,uslot 2 12 40 4

A slot includes plural symbols (e.g., 14 or 12 symbols) in the timedomain. For each numerology (e.g. subcarrier spacing) and carrier, aresource grid of Nsize,ugrid,x*NRBsc subcarriers and Nsubframe,usymbOFDM symbols is defined, starting at common resource block (CRB)Nstart,ugrid indicated by higher-layer signaling (e.g. radio resourcecontrol (RRC) signaling), where Nsize,ugrid,x is the number of resourceblocks (RBs) in the resource grid and the subscript x is DL for downlinkand UL for uplink. NRBsc is the number of subcarriers per RB. In the3GPP based wireless communication system, NRBsc is 12 generally. Thereis one resource grid for a given antenna port p, subcarrier spacingconfiguration u, and transmission direction (DL or UL). The carrierbandwidth Nsize,ugrid for subcarrier spacing configuration u is given bythe higher-layer parameter (e.g. RRC parameter). Each element in theresource grid for the antenna port p and the subcarrier spacingconfiguration u is referred to as a resource element (RE) and onecomplex symbol may be mapped to each RE. Each RE in the resource grid isuniquely identified by an index k in the frequency domain and an index 1representing a symbol location relative to a reference point in the timedomain. In the 3GPP based wireless communication system, an RB isdefined by 12 consecutive subcarriers in the frequency domain. In the3GPP NR system, RBs are classified into CRBs and physical resourceblocks (PRBs). CRBs are numbered from 0 and upwards in the frequencydomain for subcarrier spacing configuration u. The center of subcarrier0 of CRB 0 for subcarrier spacing configuration u coincides with ‘pointA’ which serves as a common reference point for resource block grids. Inthe 3GPP NR system, PRBs are defined within a bandwidth part (BWP) andnumbered from 0 to NsizeBWP,i-1, where i is the number of the bandwidthpart. The relation between the physical resource block nPRB in thebandwidth part i and the common resource block nCRB is as follows:nPRB=nCRB+NsizeBWP,i, where NsizeBWP,i is the common resource blockwhere bandwidth part starts relative to CRB 0. The BWP includes aplurality of consecutive RBs. A carrier may include a maximum of N(e.g., 5) BWPs. A UE may be configured with one or more BWPs on a givencomponent carrier. Only one BWP among BWPs configured to the UE canactive at a time. The active BWP defines the UE's operating bandwidthwithin the cell's operating bandwidth.

In the present disclosure, the term “cell” may refer to a geographicarea to which one or more nodes provide a communication system, or referto radio resources. A “cell” of a geographic area may be understood ascoverage within which a node can provide service using a carrier and a“cell” as radio resources (e.g. time-frequency resources) is associatedwith bandwidth (BW) which is a frequency range configured by thecarrier. The “cell” associated with the radio resources is defined by acombination of downlink resources and uplink resources, for example, acombination of a downlink (DL) component carrier (CC) and a uplink (UL)CC. The cell may be configured by downlink resources only, or may beconfigured by downlink resources and uplink resources. Since DLcoverage, which is a range within which the node is capable oftransmitting a valid signal, and UL coverage, which is a range withinwhich the node is capable of receiving the valid signal from the UE,depends upon a carrier carrying the signal, the coverage of the node maybe associated with coverage of the “cell” of radio resources used by thenode. Accordingly, the term “cell” may be used to represent servicecoverage of the node sometimes, radio resources at other times, or arange that signals using the radio resources can reach with validstrength at other times.

In carrier aggregation (CA), two or more CCs are aggregated. A UE maysimultaneously receive or transmit on one or multiple CCs depending onits capabilities. CA is supported for both contiguous and non-contiguousCCs. When CA is configured the UE only has one radio resource control(RRC) connection with the network. At RRC connectionestablishment/re-establishment/handover, one serving cell provides thenon-access stratum (NAS) mobility information, and at RRC connectionre-establishment/handover, one serving cell provides the security input.This cell is referred to as the Primary Cell (PCell). The PCell is acell, operating on the primary frequency, in which the UE eitherperforms the initial connection establishment procedure or initiates theconnection re-establishment procedure. Depending on UE capabilities,Secondary Cells (SCells) can be configured to form together with thePCell a set of serving cells. An SCell is a cell providing additionalradio resources on top of Special Cell. The configured set of servingcells for a UE therefore always consists of one PCell and one or moreSCells. For dual connectivity operation, the term Special Cell (SpCell)refers to the PCell of the master cell group (MCG) or the PSCell of thesecondary cell group (SCG). An SpCell supports PUCCH transmission andcontention-based random access, and is always activated. The MCG is agroup of serving cells associated with a master node, comprising of theSpCell (PCell) and optionally one or more SCells. The SCG is the subsetof serving cells associated with a secondary node, comprising of thePSCell and zero or more SCells, for a UE configured with dualconnectivity (DC). For a UE in RRC_CONNECTED not configured with CA/DCthere is only one serving cell comprising of the PCell. For a UE inRRC_CONNECTED configured with CA/DC the term “serving cells” is used todenote the set of cells comprising of the SpCell(s) and all SCells. InDC, two MAC entities are configured in a UE: one for the MCG and one forthe SCG.

FIG. 8 illustrates a data flow example in the 3GPP NR system.

In FIG. 8 , “RB” denotes a radio bearer, and “H” denotes a header. Radiobearers are categorized into two groups: data radio bearers (DRB) foruser plane data and signaling radio bearers (SRB) for control planedata. The MAC PDU is transmitted/received using radio resources throughthe PHY layer to/from an external device. The MAC PDU arrives to the PHYlayer in the form of a transport block.

In the PHY layer, the uplink transport channels UL-SCH and RACH aremapped to their physical channels PUSCH and PRACH, respectively, and thedownlink transport channels DL-SCH, BCH and PCH are mapped to PDSCH,PBCH and PDSCH, respectively. In the PHY layer, uplink controlinformation (UCI) is mapped to PUCCH, and downlink control information(DCI) is mapped to PDCCH. A MAC PDU related to UL-SCH is transmitted bya UE via a PUSCH based on an UL grant, and a MAC PDU related to DL-SCHis transmitted by a BS via a PDSCH based on a DL assignment.

Data unit(s) (e.g. PDCP SDU, PDCP PDU, RLC SDU, RLC PDU, RLC SDU, MACSDU, MAC CE, MAC PDU) in the present disclosure is(are)transmitted/received on a physical channel (e.g. PDSCH, PUSCH) based onresource allocation (e.g. UL grant, DL assignment). In the presentdisclosure, uplink resource allocation is also referred to as uplinkgrant, and downlink resource allocation is also referred to as downlinkassignment. The resource allocation includes time domain resourceallocation and frequency domain resource allocation. In the presentdisclosure, an uplink grant is either received by the UE dynamically onPDCCH, in a Random Access Response, or configured to the UEsemi-persistently by RRC. In the present disclosure, downlink assignmentis either received by the UE dynamically on the PDCCH, or configured tothe UE semi-persistently by RRC signaling from the BS.

FIG. 9 shows an example of possible RRC states in a wirelesscommunication system to which technical features of the presentdisclosure can be applied.

Referring to FIG. 9 , there may be 3 possible RRC states in a wirelesscommunication system (i.e., RRC_IDLE, RRC_CONNECTED and/or RRC_IDLE).

In RRC_IDLE (or, idle mode/state), RRC context for communication betweena UE and a network may not be established in RAN, and the UE may notbelong to a specific cell. Also, in RRC_IDLE, there is no core networkconnection for the UE. Since the device remains in sleep mode in most ofthe time to reduce battery consumption, data transfer between the UE andthe network may not occur. UEs in RRC_IDLE may periodically wake-up toreceive paging messages from the network. Mobility may be handled by theUE through cell reselection. Since uplink synchronization is notmaintained, the UE may not perform uplink transmission other thantransmissions for random access (e.g., random access preambletransmission) to move to RRC_CONNECTED.

In RRC_CONNECTED (or, connected state/mode), RRC context forcommunication between a UE and a network may be established in RAN.Also, in RRC_CONNECTED, core network connection is established for theUE. Since the UE belongs to a specific cell, cell-radio networktemporary identifier (C-RNTI) for signallings between the UE and thenetwork may be configured for the UE. Data transfer between the UE andthe network may occur. Mobility may be handled by the network - that is,the UE may provide measurement report to the network, and the networkmay transmit mobility commands to the UE to perform a mobility. Uplinktime alignment may need to be established based on a random access andmaintained for data transmission.

In RRC_INACTIVE (or, inactive state/mode), RRC context for communicationbetween a UE and a network may be kept in RAN. Data transfer between theUE and the network may not occur. Since core network connection may alsobe kept for the UE, the UE may fast transit to a connected state fordata transfer. In the transition, core network signaling may not beneeded. The RRC context may be already established in the network andidle-to-active transitions can be handled in the RAN. The UE may beallowed to sleep in a similar way as in RRC_IDLE, and mobility may behandled through cell reselection without involvement of the network. TheRRC_INCATIVE may be construed as a mix of the idle state and theconnected state.

As illustrated in FIG. 9 , the UE may transit to RRC_CONNECTED fromRRC_IDLE by performing initial attach procedure or RRC connectionestablishment procedure. The UE may transit to RRC_IDLE fromRRC_CONNECTED when detach, RRC connection release and/or connectionfailure (e.g., radio link failure (RLF)) has occurred. The UE maytransit to RRC_INACTIVE from RRC_INACTIVE when RRC connection issuspended, and transit to RRC_CONNECTED from RRC_INACTIVE when RRCconnection is resume. The UE may transit to RRC_IDLE from RRC_INACTIVEwhen connection failure such as RLF has occurred.

Hereinafter, cell selection process is described.

Cell selection may be performed by one of the following two proceduresa) and b):

a) Initial cell selection (no prior knowledge of which RF channels areNR frequencies):

The UE shall scan all radio frequency (RF) channels in the NR bandsaccording to capabilities of the UE to find a suitable cell. On eachfrequency, the UE may only need to search for the strongest cell. Once asuitable cell is found, the suitable cell shall be selected.

b) Cell selection by leveraging stored information:

This procedure may require stored information of frequencies andoptionally also information on cell parameters from previously receivedmeasurement control information elements or from previously detectedcells. Once the UE has found a suitable cell, the UE shall select thesuitable cell. If no suitable cell is found, the initial cell selectionprocedure in a) shall be started.

In the cell selection process, priorities between different frequenciesor RATs provided to the UE by system information or dedicated signalingmay not be used.

The cell selection criterion S may be fulfilled when Srxlev>0 ANDSqual>0, where i)Srxlev=Q_(rxlevmeas)−(Q_(rxlevmin)+Q_(rxlevminoffset))−P_(compensation)−Qoffset_(temp);and ii)Squal=Q_(qualmeas)−(Q_(qualmin)+Q_(qualminoffset))−Qoffset_(temp).Parameters in the above equations i) and ii) may be defined as thefollowing table 5:

TABLE 5 Srxlev Cell selection RX level value (dB) Squal Cell selectionquality value (dB) Qoffset_(temp) Offset temporarily applied to a cell(dB) Q_(rxlevmeas) Measured cell RX level value (RSRP) Q_(qualmeas)Measured cell quality value (RSRQ) Q_(rxlevmin) Minimum required RXlevel in the cell (dBm). If the UE supports SUL frequency for this cell,Qrxlevmin is obtained from q-RxLevMinSUL, if present, in SIB1, SIB2 andSIB4, additionally, if Q_(rxlevminoffsetcellSUL) is present in SIB3 andSIB4 for the concerned cell, this cell specific offset is added to thecorresponding Qrxlevmin to achieve the required minimum RX level in theconcerned cell; else Qrxlevmin is obtained from q-RxLevMin in SIB1, SIB2and SIB4, additionally, if Q_(rxlevminoffsetcell) is present in SIB3 andSIB4 for the concerned cell, this cell specific offset is added to thecorresponding Qrxlevmin to achieve the required minimum RX level in theconcerned cell. Q_(qualmin) Minimum required quality level in the cell(dB). Additionally, if Q_(qualminoffsetcell) is signalled for theconcerned cell, this cell specific offset is added to achieve therequired minimum quality level in the concerned cell. Q_(rxlevminoffset)Offset to the signalled Q_(rxlevmin) taken into account in the Srxlevevaluation as a result of a periodic search for a higher priority PLMNwhile camped normally in a VPLMN, as specified in TS 23.122 [9].Q_(qualminoffset) Offset to the signalled Q_(qualmin) taken into accountin the Squal evaluation as a result of a periodic search for a higherpriority PLMN while camped normally in a VPLMN, as specified in TS23.122 [9]. P_(compensation) If the UE supports the additionalPmax inthe NR-NS- PmaxList, if present, in SIB1, SIB2 and SIB4: max(P_(EMAX1) −P_(PowerClass), 0) − (min(P_(EMAX2), P_(PowerClass)) − min(P_(EMAX1),P_(PowerClass))) (dB); else: max(P_(EMAX1) − P_(PowerClass), 0) (dB)P_(EMAX1), P_(EMAX2) Maximum TX power level of a UE may use whentransmitting on the uplink in the cell (dBm) defined as Pemax in TS38.101 [15]. If UE supports SUL frequency for this cell, P_(EMAX1) andP_(EMAX2) are obtained from the p- Max for SUL in SIB1 andNR-NS-PmaxList for SUL respectively in SIB1, SIB2 and SIB4 as specifiedin TS 38.331 [3], else P_(EMAX1) and P_(EMAX2) are obtained from thep-Max and NR-NS-PmaxList respectively in SIB1, SIB2 and SIB4 for normalUL as specified in TS 38.331 [3]. P_(PowerClass) Maximum RF output powerof the UE (dBm) according to the UE power class as defined in TS38.101-1 [15].

The signaled values Q_(rxlevminoffset) and Q_(qualminoffset) may only beapplied when a cell is evaluated for cell selection as a result of aperiodic search for a higher priority PLMN while camped normally in aVPLMN. During this periodic search for higher priority PLMN, the UE maycheck the S criteria of a cell using parameter values stored from adifferent cell of this higher priority PLMN. Hereinafter, cellreselection process is described.

Absolute priorities of different NR frequencies or inter-RAT frequenciesmay be provided to the UE in the system information, in the RRCReleasemessage, or by inheriting from another RAT at inter-RAT cell(re)selection. In the case of system information, an NR frequency orinter-RAT frequency may be listed without providing a priority (i.e. thefield cellReselectionPriority is absent for that frequency). Ifpriorities are provided in dedicated signaling, the UE shall ignore allthe priorities provided in system information. If UE is in camped on anycell state, UE shall only apply the priorities provided by systeminformation from current cell, and the UE may preserve prioritiesprovided by dedicated signaling and deprioritisationReq received inRRCRelease unless specified otherwise. When the UE in camped normallystate has only dedicated priorities other than for the currentfrequency, the UE shall consider the current frequency to be the lowestpriority frequency (i.e., lower than any of the network configuredvalues).

The UE shall only perform cell reselection evaluation for NR frequenciesand inter-RAT frequencies that are given in system information and forwhich the UE has a priority provided.

In case UE receives RRCRelease with deprioritisationReq, UE shallconsider current frequency and stored frequencies due to the previouslyreceived RRCRelease with deprioritisationReq or all the frequencies ofNR to be the lowest priority frequency (i.e. lower than any of thenetwork configured values) while T325 is running irrespective of campedRAT. The UE shall delete the stored deprioritisation request(s) when aPLMN selection is performed on request by NAS.

The UE should search for a higher priority layer for cell reselection assoon as possible after the change of priority. The minimum relatedperformance requirements may be still applicable.

The UE shall delete priorities provided by dedicated signaling when i)the UE enters a different RRC state; ii) the optional validity time ofdedicated priorities (T320) expires; and/or iii) a PLMN selection isperformed on request by NAS. Equal priorities between RATs may not besupported.

The UE shall not consider any black listed cells as candidate for cellreselection.

The UE in RRC_IDLE state shall inherit the priorities provided bydedicated signaling and the remaining validity time (i.e. T320 in NR andE-UTRA), if configured, at inter-RAT cell (re)selection. The network mayassign dedicated cell reselection priorities for frequencies notconfigured by system information.

To limit needed measurements, if the serving cell fulfillsSrxlev>S_(IntraSearchP) and Squal>S_(IntraSearchQ), the UE may choosenot to perform intra-frequency measurements. Otherwise, the UE shallperform intra-frequency measurements.

The UE shall apply the following rules for NR inter-frequencies andinter-RAT frequencies which are indicated in system information and forwhich the UE has priority provided:

Rule 1) For a NR inter-frequency or inter-RAT frequency with areselection priority higher than the reselection priority of the currentNR frequency, the UE shall perform measurements of higher priority NRinter-frequency or inter-RAT frequencies.

Rule 2) For a NR inter-frequency with an equal or lower reselectionpriority than the reselection priority of the current NR frequency andfor inter-RAT frequency with lower reselection priority than thereselection priority of the current NR frequency, if the serving cellfulfills Srxlev>S_(nonIntraSearchP) and Squal>S_(nonIntraSearchQ), theUE may choose not to perform measurements of NR inter-frequencies orinter-RAT frequency cells of equal or lower priority. Otherwise, the UEshall perform measurements of NR inter-frequencies or inter-RATfrequency cells of equal or lower priority.

If threshServingLowQ is broadcast in system information and more than 1second has elapsed since the UE camped on the current serving cell, cellreselection to a cell on a higher priority NR frequency or inter-RATfrequency than the serving frequency shall be performed if a cell of ahigher priority NR or EUTRAN RAT/frequency fulfillsSqual>Thresh_(X, HighQ) during a time interval Treselection_(RAT).

Otherwise, cell reselection to a cell on a higher priority NR frequencyor inter-RAT frequency than the serving frequency shall be performed ifi) a cell of a higher priority RAT/frequency fulfillsSrxlev>Thresh_(X, HighP) during a time interval Treselection_(RAT); andii) more than 1 second has elapsed since the UE camped on the currentserving cell.

Cell reselection to a cell on an equal priority NR frequency shall bebased on ranking for intra-frequency cell reselection.

If threshServingLowQ is broadcast in system information and more than 1second has elapsed since the UE camped on the current serving cell, cellreselection to a cell on a lower priority NR frequency or inter-RATfrequency than the serving frequency shall be performed if the servingcell fulfills Squal<Thresh_(Serving, LowQ) and a cell of a lowerpriority NR or E-UTRAN RAT/frequency fulfills Squal>Thresh_(X, LowQ)during a time interval Treselection_(RAT).

Otherwise, cell reselection to a cell on a lower priority NR frequencyor inter-RAT frequency than the serving frequency shall be performed ifi) the serving cell fulfills Srxlev<Thresh_(Serving, LowP) and a cell ofa lower priority RAT/frequency fulfills Srxlev>Thresh_(X, LowP) during atime interval Treselection_(RAT); and ii) more than 1 second has elapsedsince the UE camped on the current serving cell.

Cell reselection to a higher priority RAT/frequency shall takeprecedence over a lower priority RAT/frequency if multiple cells ofdifferent priorities fulfill the cell reselection criteria.

If more than one cell meets the above criteria: the UE shall reselect

-   -   If the highest-priority frequency is an NR frequency, the UE        shall reselect the highest ranked cell among the cells on the        highest priority frequency(ies) meeting the criteria;    -   If the highest-priority frequency is from another RAT, the UE        shall reselect the strongest cell among the cells on the highest        priority frequency(ies) meeting the criteria of that RAT.

The cell-ranking criterion R_(s) for serving cell and R_(n) forneighbouring cells is defined by i)R_(s)=Q_(meas,s)+Q_(hyst)−Qoffset_(temp); and ii)R_(n)=Q_(meas,n)−Qoffset−Qoffset_(temp). The parameters in the aboveequations may be defined as table 6 below:

TABLE 6 Q_(meas) RSRP measurement quantity used in cell reselections.Qoffset For intra-frequency: Equals to Qoffset_(s,n), if Qoffset_(s,n)is valid, otherwise this equals to zero.For inter- frequency: Equals toQoffset_(s,n) plus QoffSet_(frequency), if Qoffset_(s,n) is valid,otherwise this equals to QoffSet_(frequency). Qoffset_(temp) Offsettemporarily applied to a cell

The UE shall perform ranking of all cells that fulfill the cellselection criterion S. The cells shall be ranked according to the Rcriteria specified above by deriving Q_(meas,n) and Q_(meas,s) andcalculating the R values using averaged RSRP results.

If rangeToBestCell is not configured, the UE shall perform cellreselection to the highest ranked cell.

If rangeToBestCell is configured, then the UE shall perform cellreselection to the cell with the highest number of beams above thethreshold (i.e. absThreshSS-BlocksConsolidation) among the cells whose Rvalue is within rangeToBestCell of the R value of the highest rankedcell. If there are multiple such cells, the UE shall perform cellreselection to the highest ranked cell among them.

In all cases, the UE shall reselect the new cell, only if i) the newcell is better than the serving cell according to the cell reselectioncriteria specified above during a time interval Treselection_(RAT); andii) more than 1 second has elapsed since the UE camped on the currentserving cell.

If rangeToBestCell is configured but absThreshSS-BlocksConsolidation isnot configured on an NR frequency, the UE may consider that there is onebeam above the threshold for each cell on that frequency.

Cell reselection parameters may be broadcast in system information andread from the serving cell. The cell reselection parameters areillustrated in table 7:

TABLE 7 absThreshSS-BlocksConsolidation This specifies minimum thresholdof the beam which can be used for selection of the highest ranked cell,if rangeToBestCell is configured. cellReselectionPriority This specifiesthe absolute priority for NR frequency or E-UTRAN frequency.cellReselectionSubPriority This specifies the fractional priority valueadded to cellReselectionPriority for NR frequency or E-UTRAN frequency.Qoffset_(s,n) This specifies the offset between the two cells.Qoffset_(frequency) Frequency specific offset for equal priority NRfrequencies. Q_(hyst) This specifies the hysteresis value for rankingcriteria. Qoffset_(temp) This specifies the additional offset to be usedfor cell selection and re-selection. It is temporarily used in case theRRC Connection Establishment fails on the cell. Q_(qualmin) Thisspecifies the minimum required quality level in the cell in dB.Q_(rxlevmin) This specifies the minimum required Rx level in the cell indBm. Q_(rxlevminoffsetcell) This specifies the cell specific Rx leveloffset in dB to Qrxlevmin. Q_(qualminoffsetcell) This specifies the cellspecific quality level offset in dB to Qqualmin. rangeToBestCell Thisspecifies the R value range which the cells whose R value is within therange can be a candidate for the highest ranked cell. It is configuredin SIB2 and used for intra- frequency and equal priority inter-frequencycell reselection and among the cells on the highest priorityfrequency(ies) for inter- frequency cell reselection within NR.Treselection_(RAT) This specifies the cell reselection timer value. Foreach target NR frequency and for each RAT other than NR, a specificvalue for the cell reselection timer is defined, which is applicablewhen evaluating reselection within NR or towards other RAT (i.e.Treselection_(RAT) for NR is Treselection_(NR), for E-UTRANTreselection_(EUTRA)). Treselection_(RAT) may not be broadcast in systeminformation but used in reselection rules by the UE for each RAT.Treselection_(NR) This specifies the cell reselection timer valueTreselection_(RAT) for NR. The parameter can be set per NR frequency.Treselection_(EUTRA) This specifies the cell reselection timer valueTreselection_(RAT) for E-UTRAN. Thresh_(X, HighP) This specifies theSrxlev threshold (in dB) used by the UE when reselecting towards ahigher priority RAT/frequency than the current serving frequency. Eachfrequency of NR and E-UTRAN might have a specific threshold.Thresh_(X, HighQ) This specifies the Squal threshold (in dB) used by theUE when reselecting towards a higher priority RAT/frequency than thecurrent serving frequency. Each frequency of NR and E-UTRAN might have aspecific threshold. Thresh_(X, LowP) This specifies the Srxlev threshold(in dB) used by the UE when reselecting towards a lower priorityRAT/frequency than the current serving frequency. Each frequency of NRand E-UTRAN might have a specific threshold. Thresh_(X, LowQ) Thisspecifies the Squal threshold (in dB) used by the UE when reselectingtowards a lower priority RAT/frequency than the current servingfrequency. Each frequency of NR and E-UTRAN might have a specificthreshold. Thresh_(Serving, LowP) This specifies the Srxlev threshold(in dB) used by the UE on the serving cell when reselecting towards alower priority RAT/ frequency. Thresh_(Serving, LowQ) This specifies theSqual threshold (in dB) used by the UE on the serving cell whenreselecting towards a lower priority RAT/ frequency. S_(IntraSearchP)This specifies the Srxlev threshold (in dB) for intra-frequencymeasurements. S_(IntraSearchQ) This specifies the Squal threshold (indB) for intra-frequency measurements. S_(nonIntraSearchP) This specifiesthe Srxlev threshold (in dB) for NR inter-frequency and inter-RATmeasurements. S_(nonIntraSearchQ) This specifies the Squal threshold (indB) for NR inter-frequency and inter-RAT measurements.

When a UE is in RRC_IDLE/INACTIVE, the UE may perform a neighbour cellmeasurement to support mobility. If the serving cell quality is abovethe threshold (If the serving cell fulfills Srxlev>S_(IntraSearchP) andSqual>S_(IntraSearchQ)), the UE may choose not to perform the neighbourcell measurement to reduce power consumption, as it is expected thatcell reselection will not occur soon. Or, when a UE is in RRC_CONNECTED,if the serving cell quality is above the threshold (i.e., s-measure),the UE may not perform the neighbour cell measurement. However, if theserving cell quality is below the threshold so that the UE is performingthe neighbour cell measurement, the UE may need to perform neighbourcell measurement on all the configured frequencies even if the servingcell quality is just below the threshold.

Therefore, it may be required to reduce the power consumption while theUE is performing neighbour cell measurement. As one of methods forreducing power consumption, measurement relaxation and/or relaxedmeasurement may be used. In the relaxed measurement, UE may relax someof requirements regarding measurement.

When the UE is required to perform measurements of intra-frequency cellsor NR inter-frequency cells or inter-RAT frequency cells according tothe measurement rules:

1> if lowMobilityEvaluation is configured and cellEdgeEvaluation is notconfigured; and

1> if the UE has performed normal intra-frequency, NR inter-frequency,or inter-RAT frequency measurements for at least T_(SearchDeltaP) after(re-)selecting a new cell; and

1> if the relaxed measurement criterion in clause 5.2.4.9.1 is fulfilledfor a period of T_(SearchDeltaP):

2> the UE may choose to perform measurements with relaxed requirementsfor intra-frequency cells;

2> if the serving cell fulfills Srxlev>S_(nonIntraSearchP) andSqual>S_(nonIntraSearchQ):

3> for any NR inter-frequency or inter-RAT frequency of higher priority,if less than 1 hour has passed since measurements of correspondingfrequency cell(s) for cell reselection were last performed; and,

3> if highPriorityMeasRelax is configured with value true:

4> the UE may choose not to perform measurement on this frequencycell(s) (i.e., the UE may skip performing measurement on this frequencycell(s));

3> else (i.e., the serving cell fulfills Srxlev≤S_(nonIntraSearchP) orSqual≤S_(nonIntraSearchQ)):

4> the UE may choose to perform measurements with relaxed requirementsfor NR inter-frequency cells or inter-RAT frequency cells;

1> if cellEdgeEvaluation is configured and lowMobilityEvaluation is notconfigured; and

1> if the relaxed measurement criterion in clause 5.2.4.9.2 isfulfilled:

2> the UE may choose to perform measurements with relaxed requirementsfor intra-frequency cells;

2> if the serving cell fulfills Srxlev≤S_(nonIntraSearchP) orSqual≤S_(nonIntraSearchQ):

3> the UE may choose to perform measurement with relaxed requirementsfor NR inter-frequency cells or inter-RAT frequency cells;

1> if both lowMobilityEvaluation and cellEdgeEvaluation are configured:

2> if the UE has performed normal intra-frequency, NR inter-frequency,or inter-RAT frequency measurements for at least T_(SearchDeltaP) after(re-)selecting a new cell; and

2> if the relaxed measurement criterion for UE with low mobility isfulfilled for a period of T_(SearchDeltaP); and

2> if the relaxed measurement criterion for UE not at cell edge isfulfilled:

3> for any intra-frequency, NR inter-frequency, or inter-RAT frequency,if less than 1 hour has passed since measurements of correspondingfrequency cell(s) for cell reselection were last performed:

4> the UE may choose not to perform measurement for measurements on thisfrequency cell(s);

2> else:

3> if the UE has performed normal intra-frequency, NR inter-frequency,or inter-RAT frequency measurements for at least T_(SearchDeltaP) after(re-)selecting a new cell, and the relaxed measurement criterion for UEwith low mobility is fulfilled for a period of T_(SearchDeltaP); or,

3> if the relaxed measurement criterion for UE not at cell edge isfulfilled:

4> if combineRelaxedMeasCondition is not configured:

5> the UE may choose to perform measurements with relaxed requirementsfor intra-frequency cells, NR inter-frequency cells of equal or lowerpriority, or inter-RAT frequency cells of lower priority;

5> if the serving cell fulfills Srxlev≤S_(nonIntraSearchP) orSqual≤S_(nonIntraSearchQ):

6> the UE may choose to perform measurements with relaxed requirementsfor NR inter-frequency cells of higher priority, or inter-RAT frequencycells of higher priority.

The above relaxed measurements and no measurement may not be applicablefor frequencies that are included in VarMeasIdleConfig, if configuredand for which the UE supports dual connectivity or carrier aggregationbetween those frequencies and the frequency of the current serving cell.

While performing neighbour cell measurement, as each UE camping on acell has different measurement results of the neighbour cells, themeasurement results of neighbour cells may need to be considered fortriggering condition of the measurement relaxation. The UE shall notperform measurement relaxation if neighbour cell quality is good enough,even if the serving cell quality satisfies the measurement relaxationcondition. This is because it is possible to perform mobility whenneighbour cell quality is good enough.

According to the present disclosure, while UE is performing neighbourcell measurement, only if the number of frequencies whose cell qualityis above a first threshold (e.g., cell quality threshold) is lower thana second threshold (e.g., triggering threshold), and/or the number offrequencies whose cell quality is lower than a first threshold (e.g.,cell quality threshold) is higher than a second threshold (e.g.,triggering threshold), the UE may perform a relaxed measurement and/ormeasurement relaxation.

FIG. 10 shows an example of a method for a relaxed measurement accordingto an embodiment of the present disclosure. Steps illustrated in FIG. 10may be performed by a wireless device and/or a UE.

Referring to FIG. 10 , in step S1001, the wireless device may receive,from a network, information for at least one of a first cell qualitythreshold or a second cell quality threshold, and information for atleast one of a first triggering threshold or a second triggeringthreshold.

In step S1003, the wireless device may identify a representative cell ofeach of a plurality of frequencies for measurement.

In step S1005, the wireless device may obtain a representative cellquality for each of the plurality of frequencies based on a measurementon the representative cell of each of the plurality of frequencies.

In step S1007, the wireless device may perform a relaxed measurement onthe plurality of frequencies based on a determination that a triggeringcondition for the relaxed measurement is satisfied. For example, thetriggering condition may comprise a first condition that a number offrequencies for which representative cell quality is higher than thefirst cell quality threshold among the plurality of frequencies is lowerthan the first triggering threshold. For another example, the triggeringcondition may comprise a second condition that a number of frequenciesfor which representative cell quality is lower than the second cellquality threshold among the plurality of frequencies is higher than thesecond triggering threshold. The triggering condition may comprise atleast one of the first condition or the second condition.

According to various embodiments, the representative cell of a frequencymay comprise a highest ranked cell on the frequency.

According to various embodiments, the representative cell of a frequencymay comprise a cell randomly selected by the wireless device among allcells on the frequency.

According to various embodiments, the representative cell quality maycomprise a cell quality of the representative cell.

According to various embodiments, the wireless device may identify afrequency for which representative cell quality is above or equal to thefirst cell quality threshold among the plurality of frequencies. Thewireless device may add the frequency to a frequency group. The wirelessdevice may perform the relaxed measurement on the plurality offrequencies based on a determination that a number of frequencies in thefrequency group is below or equal to the first triggering threshold.

According to various embodiments, the wireless device may identify afrequency for which representative cell quality is below or equal to thesecond cell quality threshold among the plurality of frequencies. Thewireless device may add the frequency to a frequency group. The wirelessdevice may perform the relaxed measurement on the plurality offrequencies based on a determination that a number of frequencies in thefrequency group is above or equal to the second triggering threshold.

According to various embodiments, the plurality of frequencies maycomprise at least one of an intra-frequency or an inter-frequency.

According to various embodiments, the first cell quality threshold maybe identical to the second cell quality threshold. The first triggeringthreshold may be identical to or different from the second triggeringthreshold.

According to various embodiments, the first triggering threshold may beidentical to the second triggering threshold. The first cell qualitythreshold may be identical to or different from the second cell qualitythreshold.

According to various embodiments, the performing of the relaxedmeasurement may comprise skipping a measurement on at least one of theplurality of frequencies.

According to various embodiments, the performing of the relaxedmeasurement may comprise performing a measurement with relaxedrequirements on the plurality of frequencies.

According to various embodiments, the performing of the measurement withrelaxed requirements may comprise performing a measurement on theplurality of frequencies based on a relaxed measurement period longerthan a measurement period required for a normal measurement. Theperforming of the measurement with relaxed requirements may compriseperforming a measurement on measurement targets on each of the pluralityof frequencies. The number of the measurement targets may be smallerthan that required for the normal measurement. The relaxed measurementperiod may be configured or signalled by a network to the wirelessdevice via at least one of downlink control information (DCI), a mediaaccess control (MAC) control element (MAC CE), or a radio resourcecontrol (RRC) signaling. The measurement targets may comprise at leastone of cells, carriers, or synchronization signal/physical broadcastchannel (SS/PBCH) blocks.

According to various embodiments, the wireless device may perform ameasurement on configured neighbor cells with a first measurementperiod. The wireless device may count the number of frequencies each ofwhich quality of a cell is above a first threshold. The wireless devicemay replace the first measurement period by a second measurement periodbased on that the counted number of frequencies is lower than a secondthreshold.

FIG. 11 shows an example of a signal flow for a relaxed measurementaccording to an embodiment of the present disclosure. In the signal flowas illustrated in FIG. 11 , a wireless device and a base station (BS)may be involved.

Referring to FIG. 11 , in step S1101, the BS may transmit, to a wirelessdevice, information for at least one of a first cell quality thresholdor a second cell quality threshold, and information for at least one ofa first triggering threshold or a second triggering threshold. Thewireless device may be configured to identify a representative cell ofeach of a plurality of frequencies for measurement. The wireless devicemay be configured to obtain a representative cell quality for each ofthe plurality of frequencies based on a measurement on therepresentative cell of each of the plurality of frequencies. Thewireless device may be configured to perform a relaxed measurement onthe plurality of frequencies based on a determination that a triggeringcondition for the relaxed measurement is satisfied. For example, thetriggering condition may comprise a first condition that a number offrequencies for which representative cell quality is higher than thefirst cell quality threshold among the plurality of frequencies is lowerthan the first triggering threshold. For another example, the triggeringcondition may comprise a second condition that a number of frequenciesfor which representative cell quality is lower than the second cellquality threshold among the plurality of frequencies is higher than thesecond triggering threshold. The triggering condition may comprise atleast one of the first condition or the second condition.

The BS in FIG. 11 may be an example of a second device 220 in FIG. 2 ,and therefore, steps of the BS as illustrated in FIG. 11 may beimplemented by the second device 220. For example, the processor 221 maybe configured to control the transceiver 223 to transmit, to a wirelessdevice, information for at least one of a first cell quality thresholdor a second cell quality threshold, and information for at least one ofa first triggering threshold or a second triggering threshold. Thewireless device may be configured to identify a representative cell ofeach of a plurality of frequencies for measurement. The wireless devicemay be configured to obtain a representative cell quality for each ofthe plurality of frequencies based on a measurement on therepresentative cell of each of the plurality of frequencies. Thewireless device may be configured to perform a relaxed measurement onthe plurality of frequencies based on a determination that a triggeringcondition for the relaxed measurement is satisfied. For example, thetriggering condition may comprise a first condition that a number offrequencies for which representative cell quality is higher than thefirst cell quality threshold among the plurality of frequencies is lowerthan the first triggering threshold. For another example, the triggeringcondition may comprise a second condition that a number of frequenciesfor which representative cell quality is lower than the second cellquality threshold among the plurality of frequencies is higher than thesecond triggering threshold. The triggering condition may comprise atleast one of the first condition or the second condition.

FIG. 12 shows an example of a method for measurement relaxation based onthe number of frequencies with cell quality according to an embodimentof the present disclosure. Steps illustrated in FIG. 12 may be performedby a wireless device and/or a UE.

Referring to FIG. 12 , in step S1201, the UE may receive neighbor cellinformation from a network. The neighbor cell information may include atleast one of a first threshold, a second threshold or cell reselectionparameters.

The first threshold may be a cell quality threshold. The first thresholdmay be used to determine whether a cell quality of a cell (e.g., highestranked cell) in a specific frequency is good enough and/or bad enough sothat the specific frequency can be included in a specific frequencygroup. For example, when/if a cell quality of a cell (e.g., highestranked cell) in a specific frequency is below and/or equal to the firstthreshold, the specific frequency may be included in the specificfrequency group. For example, when/if a cell quality of a cell (e.g.,highest ranked cell) in a specific frequency is above and/or equal tothe first threshold, the specific frequency may be included in thespecific frequency group.

The second threshold may be a threshold for determining how large orsmall the number of frequencies in the specific frequency groupmentioned above is. The second threshold may be called a triggeringthreshold. The second threshold may be used to determine whether atriggering condition of measurement relaxation is satisfied or not.Whether a triggering condition of measurement relaxation is satisfied ornot may be determined based on the number of frequencies in the specificfrequency group and the second threshold. For example, when the numberof frequencies in the specific frequency group is above and/or equal tothe second threshold, the measurement relaxation may be triggered. Foranother example, when the number of frequencies in the specificfrequency group is below and/or equal to the second threshold, themeasurement relaxation may be triggered.

The first threshold may be frequency-specific or cell-specific.

If the UE is in RRC_IDLE or RRC_INACTIVE, the neighbour cell informationmay be provided via a broadcast system information (e.g., systeminformation block type 2 (SIB2), SIB3, SIB4 and/or SIB5 in NR, SIB3,SIB4, SIB5 and/or SIB6 in LTE). Each cell may broadcast different SIB.

If the UE is in RRC_CONNECTED, the neighbour cell information may beprovided via dedicated signaling.

In step S1203, the UE may perform a neighbour cell measurement based onthe neighbour cell information. For the neighbour cell measurement, theUE may perform measurement on the cells in intra-frequency and/orinter-frequency.

In step S1205, the UE may evaluate a cell quality of cells in eachfrequency based on the result of the neighbor cell measurement. For theevaluation of the cell quality, cell reselection parameters received instep S1201 may be used. Result of the cell quality evaluation maycomprise S value, R value, reference signal received power (RSRP) and/orreference signal received quality (RSRQ).

In step S1207, the UE may compare a cell quality of a representativecell of each frequency with a first threshold. The representative cellof a frequency may be the highest ranked cell of the frequency. Therepresentative cell of a frequency may be randomly chosen among thecells in the frequency.

In step S1209, the UE may perform a relaxed measurement on thefrequencies which may be included in the neighbor cell information,based on the result of the comparison and a second threshold.

For example, based on a result of the comparison between the cellquality of the representative cell of each frequency and the firstthreshold, the UE may count the number of frequencies for which a cellquality of the representative cell is higher than the first threshold(e.g., cell quality threshold). If the number of frequencies counted bythe UE is lower than the second threshold (e.g., triggering threshold),the UE may perform a relaxed measurement on the frequencies which may beincluded in the neighbor cell information.

For another example, based on a result of the comparison between thecell quality of the representative cell of each frequency and the firstthreshold, the UE may counts the number of frequencies for which a cellquality of the representative cell is lower than the first threshold(e.g., cell quality threshold). If the number of frequencies counted bythe UE is higher than the second threshold (e.g., triggering threshold),the UE may perform a relaxed measurement on the frequencies which may beincluded in the neighbor cell information.

According to various embodiments, for the relaxed measurement on afrequency, the UE may i) skip performing a measurement on the frequency(i.e., not perform a measurement on the frequency), and/or ii) perform ameasurement with relaxed requirements on the frequency. To perform ameasurement with relaxed requirements on the frequency, the UE may:

-   -   replace a required measurement period of the frequency with a        second measurement period which may be provided via the neighbor        cell information;    -   replace a required measurement period of intra-inter-frequency        or inter-RAT E-UTRAN cells with a second measurement period,        which may be provided via the neighbor cell information; and/or    -   reduce the required number of cells, carriers and/or        synchronization signal/physical broadcast channel (SS/PBCH)        blocks on the frequency.

In the above, the second measurement period may be provided perfrequency. Also, the second measurement period may be longer than therequired measurement period.

According to various embodiments, performing the relaxed measurement maybe lasted for a certain time period.

According to the present disclosure, not only whether serving cellsatisfies conditions for the relaxed measurement (e.g., relaxedmeasurement criterion for UE with low mobility and/or relaxedmeasurement criterion for UE not at cell edge), but also neighbour cellmeasurement results may be considered for triggering relaxedmeasurement. Even if serving cell quality satisfies relaxed measurementcondition/criterion, if the neighbour cell quality is good, the UE maynot need to perform a relaxed measurement on the neighbour cells.Therefore, while serving cell quality satisfies relaxed measurementcondition/criterion, only if the number of frequencies for whichrepresentative cell quality is higher than the first threshold is lowerthan the second threshold, and/or the number of frequencies for whichrepresentative cell quality is lower than the first threshold is higherthan the second threshold, the UE may perform a relaxed measurement onthe neighbour cells.

For example, suppose six frequencies are configured for neighbour cellmeasurement. If four of the six frequencies have highest ranked cellwhose cell quality is higher than a configured cell quality threshold,the UE may determine that neighbour cells are under good radiocondition. In this case, even if serving cell quality satisfies arelaxed measurement condition/criterion, it would be better not toperform a relaxed measurement on the frequencies. The present disclosuremay enable the UE to perform a relaxed measurement based on not onlywhether a serving cell satisfies a triggering condition for a relaxedmeasurement, but also whether neighbour cell(s) satisfy a triggeringcondition for a relaxed measurement.

FIG. 13 shows a UE to implement an embodiment of the present disclosure.The present disclosure described above for UE side may be applied tothis embodiment. The UE in FIG. 13 may be an example of first device 213as illustrated in FIG. 2 .

A UE includes a processor 1310 (i.e., processor 211), a power managementmodule 1311, a battery 1312, a display 1313, a keypad 1314, a subscriberidentification module (SIM) card 1315, a memory 1320 (i.e., memory 212),a transceiver 1330 (i.e., transceiver 213), one or more antennas 1331, aspeaker 1340, and a microphone 1341.

The processor 1310 may be configured to implement proposed functions,procedures and/or methods described in this description. Layers of theradio interface protocol may be implemented in the processor 1310. Theprocessor 1310 may include application-specific integrated circuit(ASIC), other chipset, logic circuit and/or data processing device. Theprocessor 1310 may be an application processor (AP). The processor 1310may include at least one of a digital signal processor (DSP), a centralprocessing unit (CPU), a graphics processing unit (GPU), a modem(modulator and demodulator). An example of the processor 1310 may befound in SNAPDRAGON™ series of processors made by Qualcomm®, EXYNOS™series of processors made by Samsung®, A series of processors made byApple®, HELIO™ series of processors made by MediaTek®, ATOM™ series ofprocessors made by Intel® or a corresponding next generation processor.

The processor 1310 may be configured to, or configured to control thetransceiver 1330 to implement steps performed by the UE and/or thewireless device throughout the disclosure.

The power management module 1311 manages power for the processor 1310and/or the transceiver 1330. The battery 1312 supplies power to thepower management module 1311. The display 1313 outputs results processedby the processor 1310. The keypad 1314 receives inputs to be used by theprocessor 1310. The keypad 1314 may be shown on the display 1313. TheSIM card 1315 is an integrated circuit that is intended to securelystore the international mobile subscriber identity (IMSI) number and itsrelated key, which are used to identify and authenticate subscribers onmobile telephony devices (such as mobile phones and computers). It isalso possible to store contact information on many SIM cards.

The memory 1320 is operatively coupled with the processor 1310 andstores a variety of information to operate the processor 1310. Thememory 1320 may include read-only memory (ROM), random access memory(RAM), flash memory, memory card, storage medium and/or other storagedevice. When the embodiments are implemented in software, the techniquesdescribed herein can be implemented with modules (e.g., procedures,functions, and so on) that perform the functions described herein. Themodules can be stored in the memory 1320 and executed by the processor1310. The memory 1320 can be implemented within the processor 1310 orexternal to the processor 1310 in which case those can becommunicatively coupled to the processor 1310 via various means as isknown in the art.

The transceiver 1330 is operatively coupled with the processor 1310, andtransmits and/or receives a radio signal. The transceiver 1330 includesa transmitter and a receiver. The transceiver 1330 may include basebandcircuitry to process radio frequency signals. The transceiver 1330controls the one or more antennas 1331 to transmit and/or receive aradio signal.

The speaker 1340 outputs sound-related results processed by theprocessor 1310. The microphone 1341 receives sound-related inputs to beused by the processor 1310.

According to various embodiments, the processor 1310 may be configuredto, or configured to control the transceiver 1330 to implement stepsperformed by the UE and/or the wireless device throughout thedisclosure. For example, the processor 1310 may be configured to controlthe transceiver 1330 to receive, from a network, information for atleast one of a first cell quality threshold or a second cell qualitythreshold, and information for at least one of a first triggeringthreshold or a second triggering threshold. The processor 1310 may beconfigured to identify a representative cell of each of a plurality offrequencies for measurement. The processor 1310 may be configured toobtain a representative cell quality for each of the plurality offrequencies based on a measurement on the representative cell of each ofthe plurality of frequencies. The processor 1310 may be configured toperform a relaxed measurement on the plurality of frequencies based on adetermination that a triggering condition for the relaxed measurement issatisfied. For example, the triggering condition may comprise a firstcondition that a number of frequencies for which representative cellquality is higher than the first cell quality threshold among theplurality of frequencies is lower than the first triggering threshold.For another example, the triggering condition may comprise a secondcondition that a number of frequencies for which representative cellquality is lower than the second cell quality threshold among theplurality of frequencies is higher than the second triggering threshold.The triggering condition may comprise at least one of the firstcondition or the second condition.

According to various embodiments, the representative cell of a frequencymay comprise a highest ranked cell on the frequency.

According to various embodiments, the representative cell of a frequencymay comprise a cell randomly selected by the wireless device among allcells on the frequency.

According to various embodiments, the representative cell quality maycomprise a cell quality of the representative cell.

According to various embodiments, the processor 1310 may be configuredto identify a frequency for which representative cell quality is aboveor equal to the first cell quality threshold among the plurality offrequencies. The processor 1310 may be configured to add the frequencyto a frequency group. The processor 1310 may be configured to performthe relaxed measurement on the plurality of frequencies based on adetermination that a number of frequencies in the frequency group isbelow or equal to the first triggering threshold.

According to various embodiments, the processor 1310 may be configuredto identify a frequency for which representative cell quality is belowor equal to the second cell quality threshold among the plurality offrequencies. The processor 1310 may be configured to add the frequencyto a frequency group. The processor 1310 may be configured to performthe relaxed measurement on the plurality of frequencies based on adetermination that a number of frequencies in the frequency group isabove or equal to the second triggering threshold.

According to various embodiments, the plurality of frequencies maycomprise at least one of an intra-frequency or an inter-frequency.

According to various embodiments, the first cell quality threshold maybe identical to the second cell quality threshold. The first triggeringthreshold may be identical to or different from the second triggeringthreshold.

According to various embodiments, the first triggering threshold may beidentical to the second triggering threshold. The first cell qualitythreshold may be identical to or different from the second cell qualitythreshold.

According to various embodiments, the performing of the relaxedmeasurement may comprise skipping a measurement on at least one of theplurality of frequencies.

According to various embodiments, the performing of the relaxedmeasurement may comprise performing a measurement with relaxedrequirements on the plurality of frequencies.

According to various embodiments, the performing of the measurement withrelaxed requirements may comprise performing a measurement on theplurality of frequencies based on a relaxed measurement period longerthan a measurement period required for a normal measurement. Theperforming of the measurement with relaxed requirements may compriseperforming a measurement on measurement targets on each of the pluralityof frequencies. The number of the measurement targets may be smallerthan that required for the normal measurement. The relaxed measurementperiod may be configured or signalled by a network to the wirelessdevice via at least one of downlink control information (DCI), a mediaaccess control (MAC) control element (MAC CE), or a radio resourcecontrol (RRC) signaling. The measurement targets may comprise at leastone of cells, carriers, or synchronization signal/physical broadcastchannel (SS/PBCH) blocks.

FIG. 14 shows another example of a wireless communication system towhich the technical features of the present disclosure can be applied.

Referring to FIG. 14 , the wireless communication system may include afirst device 1410 (i.e., first device 210) and a second device 1420(i.e., second device 220).

The first device 1410 may include at least one transceiver, such as atransceiver 1411, and at least one processing chip, such as a processingchip 1412. The processing chip 1412 may include at least one processor,such a processor 1413, and at least one memory, such as a memory 1414.The memory may be operably connectable to the processor 1413. The memory1414 may store various types of information and/or instructions. Thememory 1414 may store a software code 1415 which implements instructionsthat, when executed by the processor 1413, perform operations of thefirst device 910 described throughout the disclosure. For example, thesoftware code 1415 may implement instructions that, when executed by theprocessor 1413, perform the functions, procedures, and/or methods of thefirst device 1410 described throughout the disclosure. For example, thesoftware code 1415 may control the processor 1413 to perform one or moreprotocols. For example, the software code 1415 may control the processor1413 to perform one or more layers of the radio interface protocol.

The second device 1420 may include at least one transceiver, such as atransceiver 1421, and at least one processing chip, such as a processingchip 1422. The processing chip 1422 may include at least one processor,such a processor 1423, and at least one memory, such as a memory 1424.The memory may be operably connectable to the processor 1423. The memory1424 may store various types of information and/or instructions. Thememory 1424 may store a software code 1425 which implements instructionsthat, when executed by the processor 1423, perform operations of thesecond device 1420 described throughout the disclosure. For example, thesoftware code 1425 may implement instructions that, when executed by theprocessor 1423, perform the functions, procedures, and/or methods of thesecond device 1420 described throughout the disclosure. For example, thesoftware code 1425 may control the processor 1423 to perform one or moreprotocols. For example, the software code 1425 may control the processor1423 to perform one or more layers of the radio interface protocol.

According to various embodiments, the first device 1410 as illustratedin FIG. 14 may comprise a wireless device. The wireless device maycomprise a transceiver 1411, a processing chip 1412. The processing chip1412 may comprise a processor 1413, and a memory 1414. The memory 1414may be operably connectable to the processor 1413. The memory 1414 maystore various types of information and/or instructions. The memory 1414may store a software code 1415 which implements instructions that, whenexecuted by the processor 1413, perform operations comprising:receiving, from a network, information for at least one of a first cellquality threshold or a second cell quality threshold, and informationfor at least one of a first triggering threshold or a second triggeringthreshold; identifying a representative cell of each of a plurality offrequencies for measurement; obtaining a representative cell quality foreach of the plurality of frequencies based on a measurement on therepresentative cell of each of the plurality of frequencies; andperforming a relaxed measurement on the plurality of frequencies basedon a determination that a triggering condition for the relaxedmeasurement is satisfied, wherein the triggering condition comprises atleast one of: a condition that a number of frequencies for whichrepresentative cell quality is higher than the first cell qualitythreshold among the plurality of frequencies is lower than the firsttriggering threshold; or a condition that a number of frequencies forwhich representative cell quality is lower than the second cell qualitythreshold among the plurality of frequencies is higher than the secondtriggering threshold.

According to various embodiments, a computer-readable medium havingrecorded thereon a program for performing each step of a method on acomputer is provided. The method comprises: receiving, from a network,information for at least one of a first cell quality threshold or asecond cell quality threshold, and information for at least one of afirst triggering threshold or a second triggering threshold; identifyinga representative cell of each of a plurality of frequencies formeasurement; obtaining a representative cell quality for each of theplurality of frequencies based on a measurement on the representativecell of each of the plurality of frequencies; and performing a relaxedmeasurement on the plurality of frequencies based on a determinationthat a triggering condition for the relaxed measurement is satisfied,wherein the triggering condition comprises at least one of: a conditionthat a number of frequencies for which representative cell quality ishigher than the first cell quality threshold among the plurality offrequencies is lower than the first triggering threshold; or a conditionthat a number of frequencies for which representative cell quality islower than the second cell quality threshold among the plurality offrequencies is higher than the second triggering threshold.

The present disclosure may be applied to various future technologies,such as AI, robots, autonomous-driving/self-driving vehicles, and/orextended reality (XR).

<AI>

AI refers to artificial intelligence and/or the field of studyingmethodology for making it. Machine learning is a field of studyingmethodologies that define and solve various problems dealt with in AI.Machine learning may be defined as an algorithm that enhances theperformance of a task through a steady experience with any task.

An artificial neural network (ANN) is a model used in machine learning.It can mean a whole model of problem-solving ability, consisting ofartificial neurons (nodes) that form a network of synapses. An ANN canbe defined by a connection pattern between neurons in different layers,a learning process for updating model parameters, and/or an activationfunction for generating an output value. An ANN may include an inputlayer, an output layer, and optionally one or more hidden layers. Eachlayer may contain one or more neurons, and an ANN may include a synapsethat links neurons to neurons. In an ANN, each neuron can output asummation of the activation function for input signals, weights, anddeflections input through the synapse. Model parameters are parametersdetermined through learning, including deflection of neurons and/orweights of synaptic connections. The hyper-parameter means a parameterto be set in the machine learning algorithm before learning, andincludes a learning rate, a repetition number, a mini batch size, aninitialization function, etc. The objective of the ANN learning can beseen as determining the model parameters that minimize the lossfunction. The loss function can be used as an index to determine optimalmodel parameters in learning process of ANN.

Machine learning can be divided into supervised learning, unsupervisedlearning, and reinforcement learning, depending on the learning method.Supervised learning is a method of learning ANN with labels given tolearning data. Labels are the answers (or result values) that ANN mustinfer when learning data is input to ANN. Unsupervised learning can meana method of learning ANN without labels given to learning data.Reinforcement learning can mean a learning method in which an agentdefined in an environment learns to select a behavior and/or sequence ofactions that maximizes cumulative compensation in each state.

Machine learning, which is implemented as a deep neural network (DNN)that includes multiple hidden layers among ANN, is also called deeplearning. Deep learning is part of machine learning. In the following,machine learning is used to mean deep learning.

FIG. 15 shows an example of an AI device to which the technical featuresof the present disclosure can be applied.

The AI device 1500 may be implemented as a stationary device or a mobiledevice, such as a TV, a projector, a mobile phone, a smartphone, adesktop computer, a notebook, a digital broadcasting terminal, a PDA, aPMP, a navigation device, a tablet PC, a wearable device, a set-top box(STB), a digital multimedia broadcasting (DMB) receiver, a radio, awashing machine, a refrigerator, a digital signage, a robot, a vehicle,etc.

Referring to FIG. 15 , the AI device 1500 may include a communicationpart 1510, an input part 1520, a learning processor 1530, a sensing part1540, an output part 1550, a memory 1560, and a processor 1570.

The communication part 1510 can transmit and/or receive data to and/orfrom external devices such as the AI devices and the AI server usingwire and/or wireless communication technology. For example, thecommunication part 1510 can transmit and/or receive sensor information,a user input, a learning model, and a control signal with externaldevices. The communication technology used by the communication part1510 may include a global system for mobile communication (GSM), a codedivision multiple access (CDMA), an LTE/LTE-A, a 5G, a WLAN, a Wi-Fi,Bluetooth™, radio frequency identification (RFID), infrared dataassociation (IrDA), ZigBee, and/or near field communication (NFC).

The input part 1520 can acquire various kinds of data. The input part1520 may include a camera for inputting a video signal, a microphone forreceiving an audio signal, and a user input part for receivinginformation from a user. A camera and/or a microphone may be treated asa sensor, and a signal obtained from a camera and/or a microphone may bereferred to as sensing data and/or sensor information. The input part1520 can acquire input data to be used when acquiring an output usinglearning data and a learning model for model learning. The input part1520 may obtain raw input data, in which case the processor 1570 or thelearning processor 1530 may extract input features by preprocessing theinput data.

The learning processor 1530 may learn a model composed of an ANN usinglearning data. The learned ANN can be referred to as a learning model.The learning model can be used to infer result values for new input datarather than learning data, and the inferred values can be used as abasis for determining which actions to perform. The learning processor1530 may perform AI processing together with the learning processor ofthe AI server. The learning processor 1530 may include a memoryintegrated and/or implemented in the AI device 1500. Alternatively, thelearning processor 1530 may be implemented using the memory 1560, anexternal memory directly coupled to the AI device 1500, and/or a memorymaintained in an external device.

The sensing part 1540 may acquire at least one of internal informationof the AI device 1500, environment information of the AI device 1500,and/or the user information using various sensors. The sensors includedin the sensing part 1540 may include a proximity sensor, an illuminancesensor, an acceleration sensor, a magnetic sensor, a gyro sensor, aninertial sensor, an RGB sensor, an IR sensor, a fingerprint recognitionsensor, an ultrasonic sensor, an optical sensor, a microphone, a lightdetection and ranging (LIDAR), and/or a radar.

The output part 1550 may generate an output related to visual, auditory,tactile, etc. The output part 1550 may include a display unit foroutputting visual information, a speaker for outputting auditoryinformation, and/or a haptic module for outputting tactile information.

The memory 1560 may store data that supports various functions of the AIdevice 1500. For example, the memory 1560 may store input data acquiredby the input part 1520, learning data, a learning model, a learninghistory, etc.

The processor 1570 may determine at least one executable operation ofthe AI device 1500 based on information determined and/or generatedusing a data analysis algorithm and/or a machine learning algorithm. Theprocessor 1570 may then control the components of the AI device 1500 toperform the determined operation. The processor 1570 may request,retrieve, receive, and/or utilize data in the learning processor 1530and/or the memory 1560, and may control the components of the AI device1500 to execute the predicted operation and/or the operation determinedto be desirable among the at least one executable operation. Theprocessor 1570 may generate a control signal for controlling theexternal device, and may transmit the generated control signal to theexternal device, when the external device needs to be linked to performthe determined operation. The processor 1570 may obtain the intentioninformation for the user input and determine the user's requirementsbased on the obtained intention information. The processor 1570 may useat least one of a speech-to-text (STT) engine for converting speechinput into a text string and/or a natural language processing (NLP)engine for acquiring intention information of a natural language, toobtain the intention information corresponding to the user input. Atleast one of the STT engine and/or the NLP engine may be configured asan ANN, at least a part of which is learned according to a machinelearning algorithm. At least one of the STT engine and/or the NLP enginemay be learned by the learning processor 1530 and/or learned by thelearning processor of the AI server, and/or learned by their distributedprocessing. The processor 1570 may collect history information includingthe operation contents of the AI device 1500 and/or the user's feedbackon the operation, etc. The processor 1570 may store the collectedhistory information in the memory 1560 and/or the learning processor1530, and/or transmit to an external device such as the AI server. Thecollected history information can be used to update the learning model.The processor 1570 may control at least some of the components of AIdevice 1500 to drive an application program stored in memory 1560.Furthermore, the processor 1570 may operate two or more of thecomponents included in the AI device 1500 in combination with each otherfor driving the application program.

FIG. 16 shows an example of an AI system to which the technical featuresof the present disclosure can be applied.

Referring to FIG. 16 , in the AI system, at least one of an AI server1620, a robot 1610 a, an autonomous vehicle 1610 b, an XR device 1610 c,a smartphone 1610 d and/or a home appliance 1610 e is connected to acloud network 1600. The robot 1610 a, the autonomous vehicle 1610 b, theXR device 1610 c, the smartphone 1610 d, and/or the home appliance 1610e to which the AI technology is applied may be referred to as AI devices1610 a to 1610 e.

The cloud network 1600 may refer to a network that forms part of a cloudcomputing infrastructure and/or resides in a cloud computinginfrastructure. The cloud network 1600 may be configured using a 3Gnetwork, a 4G or LTE network, and/or a 5G network. That is, each of thedevices 1610 a to 1610 e and 1620 consisting the AI system may beconnected to each other through the cloud network 1600. In particular,each of the devices 1610 a to 1610 e and 1620 may communicate with eachother through a base station, but may directly communicate with eachother without using a base station.

The AI server 1620 may include a server for performing AI processing anda server for performing operations on big data. The AI server 1620 isconnected to at least one or more of AI devices constituting the AIsystem, i.e. the robot 1610 a, the autonomous vehicle 1610 b, the XRdevice 1610 c, the smartphone 1610 d and/or the home appliance 1610 ethrough the cloud network 1600, and may assist at least some AIprocessing of the connected AI devices 1610 a to 1610 e. The AI server1620 can learn the ANN according to the machine learning algorithm onbehalf of the AI devices 1610 a to 1610 e, and can directly store thelearning models and/or transmit them to the AI devices 1610 a to 1610 e.The AI server 1620 may receive the input data from the AI devices 1610 ato 1610 e, infer the result value with respect to the received inputdata using the learning model, generate a response and/or a controlcommand based on the inferred result value, and transmit the generateddata to the AI devices 1610 a to 1610 e. Alternatively, the AI devices1610 a to 1610 e may directly infer a result value for the input datausing a learning model, and generate a response and/or a control commandbased on the inferred result value.

Various embodiments of the AI devices 1610 a to 1610 e to which thetechnical features of the present disclosure can be applied will bedescribed. The AI devices 1610 a to 1610 e shown in FIG. 16 can be seenas specific embodiments of the AI device 1500 shown in FIG. 15 .

The present disclosure can have various advantageous effects.

For example, the UE may determine whether to perform a relaxedmeasurement by considering not only a serving cell quality but also aneighbor cell quality so that the UE can perform a mobility when theneighbor cell quality is good enough.

For example, by considering not only a serving cell quality but also aneighbor cell quality, the UE can perform a relaxed measurement when theneighbor cell quality is bad enough.

Advantageous effects which can be obtained through specific embodimentsof the present disclosure are not limited to the advantageous effectslisted above. For example, there may be a variety of technical effectsthat a person having ordinary skill in the related art can understandand/or derive from the present disclosure. Accordingly, the specificeffects of the present disclosure are not limited to those explicitlydescribed herein, but may include various effects that may be understoodor derived from the technical features of the present disclosure.

In view of the exemplary systems described herein, methodologies thatmay be implemented in accordance with the disclosed subject matter havebeen described with reference to several flow diagrams. While forpurposed of simplicity, the methodologies are shown and described as aseries of steps or blocks, it is to be understood and appreciated thatthe claimed subject matter is not limited by the order of the steps orblocks, as some steps may occur in different orders or concurrently withother steps from what is depicted and described herein. Moreover, oneskilled in the art would understand that the steps illustrated in theflow diagram are not exclusive and other steps may be included or one ormore of the steps in the example flow diagram may be deleted withoutaffecting the scope of the present disclosure.

Claims in the present description can be combined in a various way. Forinstance, technical features in method claims of the present descriptioncan be combined to be implemented or performed in an apparatus, andtechnical features in apparatus claims can be combined to be implementedor performed in a method. Further, technical features in method claim(s)and apparatus claim(s) can be combined to be implemented or performed inan apparatus. Further, technical features in method claim(s) andapparatus claim(s) can be combined to be implemented or performed in amethod. Other implementations are within the scope of the followingclaims.

1. A method performed by a wireless device in a wireless communicationsystem, the method comprising: receiving, from a network, informationfor at least one of a first cell quality threshold or a second cellquality threshold, and information for at least one of a firsttriggering threshold or a second triggering threshold; identifying arepresentative cell of each of a plurality of frequencies formeasurement; obtaining a representative cell quality for each of theplurality of frequencies based on a measurement on the representativecell of each of the plurality of frequencies; and performing a relaxedmeasurement on the plurality of frequencies based on a determinationthat a triggering condition for the relaxed measurement is satisfied,wherein the triggering condition comprises at least one of: a conditionthat a number of frequencies for which representative cell quality ishigher than the first cell quality threshold among the plurality offrequencies is lower than the first triggering threshold; or a conditionthat a number of frequencies for which representative cell quality islower than the second cell quality threshold among the plurality offrequencies is higher than the second triggering threshold.
 2. Themethod of claim 1, wherein the representative cell of a frequencycomprises a highest ranked cell on the frequency.
 3. The method of claim1, wherein the representative cell of a frequency comprises a cellrandomly selected by the wireless device among all cells on thefrequency.
 4. The method of claim 1, wherein the representative cellquality comprises a cell quality of the representative cell.
 5. Themethod of claim 1, further comprising: identifying a frequency for whichrepresentative cell quality is above or equal to the first cell qualitythreshold among the plurality of frequencies; and adding the frequencyto a frequency group, wherein the performing of the relaxed measurementcomprises performing the relaxed measurement on the plurality offrequencies based on a determination that a number of frequencies in thefrequency group is below or equal to the first triggering threshold. 6.The method of claim 1, further comprising: identifying a frequency forwhich representative cell quality is below or equal to the second cellquality threshold among the plurality of frequencies; and adding thefrequency to a frequency group, wherein the performing of the relaxedmeasurement comprises performing the relaxed measurement on theplurality of frequencies based on a determination that a number offrequencies in the frequency group is above or equal to the secondtriggering threshold.
 7. The method of claim 1, wherein the plurality offrequencies comprise at least one of an intra-frequency or aninter-frequency.
 8. The method of claim 1, wherein the first cellquality threshold is identical to the second cell quality threshold, andwherein the first triggering threshold is identical to or different fromthe second triggering threshold.
 9. The method of claim 1, wherein thefirst triggering threshold is identical to the second triggeringthreshold, and wherein the first cell quality threshold is identical toor different from the second cell quality threshold.
 10. The method ofclaim 1, wherein the performing of the relaxed measurement comprisesskipping a measurement on at least one of the plurality of frequencies.11. The method of claim 1, wherein the performing of the relaxedmeasurement comprises performing a measurement with relaxed requirementson the plurality of frequencies.
 12. The method of claim 11, wherein theperforming of the measurement with relaxed requirements comprises atleast one of: performing a measurement on the plurality of frequenciesbased on a relaxed measurement period longer than a measurement periodrequired for a normal measurement; or performing a measurement onmeasurement targets on each of the plurality of frequencies, wherein anumber of the measurement targets is smaller than that required for thenormal measurement, wherein the relaxed measurement period is configuredor signalled by a network to the wireless device via at least one ofdownlink control information (DCI), a media access control (MAC) controlelement (MAC CE), or a radio resource control (RRC) signaling, andwherein the measurement targets comprise at least one of cells,carriers, or synchronization signal/physical broadcast channel (SS/PBCH)blocks.
 13. The method of claim 1, wherein the wireless device is incommunication with at least one of a user equipment, a network, orautonomous vehicles other than the wireless device.
 14. A wirelessdevice in a wireless communication system comprising: a transceiver; amemory; and at least one processor operatively coupled to thetransceiver and the memory, and configured to: control the transceiverto receive, from a network, information for at least one of a first cellquality threshold or a second cell quality threshold, and informationfor at least one of a first triggering threshold or a second triggeringthreshold; identify a representative cell of each of a plurality offrequencies for measurement; obtain a representative cell quality foreach of the plurality of frequencies based on a measurement on therepresentative cell of each of the plurality of frequencies; and performa relaxed measurement on the plurality of frequencies based on adetermination that a triggering condition for the relaxed measurement issatisfied, wherein the triggering condition comprises at least one of: acondition that a number of frequencies for which representative cellquality is higher than the first cell quality threshold among theplurality of frequencies is lower than the first triggering threshold;or a condition that a number of frequencies for which representativecell quality is lower than the second cell quality threshold among theplurality of frequencies is higher than the second triggering threshold.15. (canceled)
 16. A computer-readable medium having recorded thereon aprogram for performing each step of a method on a computer, the methodcomprising: receiving, from a network, information for at least one of afirst cell quality threshold or a second cell quality threshold, andinformation for at least one of a first triggering threshold or a secondtriggering threshold; identifying a representative cell of each of aplurality of frequencies for measurement; obtaining a representativecell quality for each of the plurality of frequencies based on ameasurement on the representative cell of each of the plurality offrequencies; and performing a relaxed measurement on the plurality offrequencies based on a determination that a triggering condition for therelaxed measurement is satisfied, wherein the triggering conditioncomprises at least one of: a condition that a number of frequencies forwhich representative cell quality is higher than the first cell qualitythreshold among the plurality of frequencies is lower than the firsttriggering threshold; or a condition that a number of frequencies forwhich representative cell quality is lower than the second cell qualitythreshold among the plurality of frequencies is higher than the secondtriggering threshold. 17-18. (canceled)